DEAR ABBY: I need your opinion. I have been with the same guy for 27 years. We never married because we were both married before, and I wasn't into doing it again. I have stuck by him through sickness, hard times and whatever else.

Four months ago I was diagnosed with small cell lung cancer. I stopped by his house this week to pick up a rug scrubber and walked in on him having sex with some woman. I feel hurt, angry, mad, sad. It's like, why? Do you think he has been doing this and he just got caught or what?

I didn't say anything. I just left. He called me later and said it was over between us because I'm sick and "can't do anything." I'm in shock. I don't know what to think. I have always been there for him. So why, now that I'm sick and I need him the most, has he turned his back on me? -- BLINDSIDED IN OHIO

DEAR BLINDSIDED: I am so, so sorry that you had to find out this way -- when the chips are down -- that the man you have been involved with for 27 years isn't much of a man after all. I DO think he has been doing this all these years.

Now it is time to marshal your friends and family and let them know what's going on. If you have been a caring and supportive friend or relative, they should be supportive during this challenging time. The American Cancer Society has support groups for people with cancer if you need someone to talk to. Its website is cancer.org. Please know you are in my thoughts and prayers for both a spiritual and physical recovery.

DEAR ABBY: My family is getting torn apart by my older brother's issue with me. It has become worse over the years, even after his marriage.

He seems to be upset with how my life is progressing, and to upset me, he has been copying everything I do. He got engaged and married around the same time I did. He also got a dog right after I did, bought a car right after me and decided he wanted to start a family as soon as my wife and I announced we are having a baby.

My parents constantly make excuses about why his actions are justified. I no longer know what to do. I tried to reconcile with him, but he rebuffed me and says he hates me. It has reached the point that I don't want to be around any of my family anymore because they defend him on everything, despite the facts. What should I do? I seem to be the only person trying to reconcile the relationship and fix/reunite my family. -- SAD SIBLING IN NEW JERSEY

DEAR SIBLING: I find it hard to believe that your family would side with a sibling who declares he "hates" his brother and refuses attempts to reconcile. It's important for your mental health that you separate emotionally from your brother. By that I mean dial back the resentment, live your life with your wife and child and stop obsessing about what your brother does. That he literally follows in your footsteps shows he either admires the choices you make, or that he has no imagination of his own. Neither of these should be a problem for YOU.

DEAR ABBY: Because my husband and I work, I take our 6-month-old to a sitter several times a week. I understand little ones tend to be mean sometimes -- hitting, biting and pushing -- but in this case, it's a little different.

My sitter cares for her 3-year-old granddaughter as well as her clients' children, and her granddaughter pushes the littler ones. I have seen her push a 1-year-old down. I have never observed any of the other children do it, only the granddaughter.

I wouldn't be so worried if my daughter were 2 and could defend herself, but she's only 6 months old. She is crawling, sitting up and standing already, and I'm gravely worried the girl will harm my infant. I don't want my baby ending up with a head injury. What can I do to try to resolve this? -- DEEPLY CONCERNED IN THE SOUTH

DEAR DEEPLY CONCERNED: Talk to the sitter about your concerns. Ask if it is possible to keep the older girl separate from the younger ones, however, the only way to be absolutely certain your little one is safe would be to change babysitters.

DEAR ABBY: I made a friend on Facebook. "Drew" and I texted through Messenger, and I went to ride four-wheelers with him one day. We hit it off great. We started dating, and he moved in with me for a few months.

In the beginning, Drew didn't mention he was working only part time. After he told me he had been moved to part time, I told him he needed to tell his boss he needed full time or a different job. I wrote a comment to that effect on their page, and his boss texted me back saying Drew can work as much as he wants! He also said Drew hasn't worked full time since he started working there.

Well, Drew got mad at me and left. I still love him. I thought he was my soul mate. Should I keep wishing we could get back together? -- FEELING LIFELESS

DEAR FEELING LIFELESS: No! In a sense, you were taken for a ride, and I'm not talking about four-wheelers. Your next soul mate should be someone who is completely honest and, preferably, fully employed. Drew is neither.

DEAR ABBY: I have been remarried for four years to a wonderful man who treats me like a queen. However, he and my 18-year-old daughter dislike each other, which causes a huge amount of stress and conflict. They fight, and I'm stuck in the middle. I don't know what I can do to resolve this problem. I love them both with all my heart! -- DESPERATE FOR PEACE

DEAR DESPERATE: I wish you had mentioned why your husband dislikes your daughter and vice versa. Is he overbearing and trying to parent her? That is YOUR job, not his.

Your daughter is no longer 14. At 18, she is now considered to be an adult, and because the "combatants" are both adults, they should act like it, be civil and refrain from turning their disagreements into open warfare. Your mistake has been allowing yourself to be placed in the middle. A better solution would be to get family counseling if your daughter plans to continue to live with you.

DEAR ABBY: I am a 46-year-old woman, about to be married for the second time. My fiance lives with me and my two children from my previous marriage.

Other than cooking breakfast and some quick snacks, he does not contribute to the household. My issue is, I pay all the bills, and he complains about the temperature inside my home. My children and I need it to be cooler. If it's too hot, we sweat and become congested, which we hate, and it makes us irritable. I tell him to put on more clothes if he is cold, but he complains to the point that I turn off the fans and air.

My question is, don't I have a right to be comfortable in the home I pay for? He doesn't pay, so he should adjust to our climate. Right? -- HOT & FRUSTRATED IN VIRGINIA

DEAR HOT & FRUSTRATED: The answers to your questions are yes and yes. And your fiance -- not you -- should invest in a portable heater, which may solve his problem.

P.S. Are you absolutely sure you want to be married to this prize? Nowhere in your letter did you say you love this person. Not once did you mention his endearing qualities. Frankly, from your description, he seems like a third child.

DEAR ABBY: My dad passed away 25 years ago when I was barely a teen. My boyfriend proposed in March, and we are planning our nuptials next fall.

As a girl, I dreamed my dad would walk me down the aisle. I would now like my uncle to step in and fill that role. He has a daughter who is older than I am. She has been married for many years. Out of respect, I would like to ask her if she's OK with my asking her father. I'm pretty sure she won't mind, but I feel asking her is the right thing to do. I'm unsure how to go about it. Any suggestions would be greatly appreciated. -- MARRYING IN MAINE

DEAR MARRYING: Congratulations on your forthcoming nuptials. What you are considering is not unusual and, frankly, it's a great compliment to your uncle. I think your idea of running it by your cousin is sensitive as well as prudent. The discussion would be more loving and productive if you conduct it in person or by phone rather than a text or email. I can see no reason why she shouldn't be thrilled for you and her dad.

DEAR ABBY: I have a job I love. My co-workers are nice, but once I punch out at the end of the day, I want to forget them. I believe that's how it should be, but some of them try to arrange meet-ups after work to hang out. Or they insist on becoming my friend on social media. I don't consider them social friends, and I don't think they need to know the details of my private life. Is there a nice way to tell these people to back off a little because we only work together? -- NINE TO FIVE IN NEW YORK

DEAR NINE TO FIVE: When you are invited to hang out after work, explain that you have things you need to do or previous commitments. And as for sharing your personal information with them online, all you have to say is that you prefer to keep your business and personal lives separate.