DEAR SOMEONE ELSE’S MOM: As I was taking out the trash the other night, I ran into an old flame in the lobby of my building. Even though we have not seen each other in years, it was still awkward, especially because things did not end well with us. He could not stop lying to me about big stuff, little stuff, and pretty much every time he opened his mouth.

When he told me he was moving into my building, I didn’t know if I should believe him or not, but I saw his name on a mailbox, so I guess he was telling the truth — for once.

I truly have no love left for this man, but I cannot entirely get past my loathing of him. I do not want him to have the satisfaction of seeing me get rattled when we meet, as we are sure to do. There is a decent gym in the building, and the older units, like mine, have not had washers and dryers installed yet. Besides myself, I know some of my friends will s##t a brick when they see him. One in particular hated him from the get-go.

How do I bump into this guy without letting him know he still drives me nuts? --- FUTURE BAD NEIGHBOR

DEAR FUTURE BAD NEIGHBOR: Why let him see he still gets your blood boiling, and not in a good way? Simply smile whenever you see him. Be polite, brief, and don’t allow him to start any conversations. Fill your friends in on the plan.

You were there first, and you should clearly demonstrate that as far as you’re concerned, he’s as important to you as the lobby wallpaper.

DEAR SOMEONE ELSE’S MOM: My girlfriend and I have been together for over two years, and even though we have separate apartments, we are usually at her place or mine every night. She comes from a strict family, headed up by her old school father, who can’t even imagine his little girl is having sex, much less practically living with a man “in sin.” So, whenever her family comes over to her place, we have to hide all my stuff and I can never be there when they arrive. I can get there later, but not before we go through this whole charade.

I love my girlfriend, and we have talked about getting married, but it really bugs me that I have to disappear to please her family. Is this an overreaction? --- THE INVISIBLE MAN

DEAR INVISIBLE MAN: Well, that depends. You don’t mention if you’ve ever discussed this situation with your girlfriend, so let’s figure you have. If you haven’t, that’s the first step you should strongly consider taking. It’s unlikely she’s clueless about the position her wanting to conceal the nature of your relationship puts you in.

After laying your cards on the table, be considerate of her position too. Most likely, she doesn’t want to hurt her parents and cause a rift in the family. If you’re seen as the reason she and her family are at odds, what does that do to how you’re viewed by her parents, especially as a prospective son-in-law?

Talk it through with your girlfriend, and choose your battle wisely. Either you offend her family now and put your girlfriend in a difficult place, or bide your time and see what the longer-term bodes.

DEAR SOMEONE ELSE’S MOM: At first I thought it was my imagination, but now I know it isn’t me. A few times after I got together with my former co-worker and friend, I noticed something went missing from my bag.

We’ve been having lunch together every two or three months, lately just at a local place with a lot of outdoor seating. I used to ask her to watch my bag when I ran inside to use the restroom, and later, when I looked for my lipstick or mascara, and one time my tampons, they weren’t there.

I don’t get it, personally. But, I also don’t want to lose a friendship over some small items disappearing, but I also worry next time it’ll be something more valuable. I’ve started keeping my handbag with me at all times when we’re together, but thinking about what I know she’s done in the past makes me wonder if I want to continue seeing her in the future.

Do I confront her, or just let it go and keep taking precautions? --- MY FRIEND HAS STICKY FINGERS

DEAR MY FRIEND HAS STICKY FINGERS: Since you have no way of proving that your friend snagged the items from your bag, there’s little point in accusing her of having taken them now, well after the fact. The only reason to do so would be if you’re planning to attempt a sort of one-person intervention, which may or may not be a good idea.

You already seem to have a handle on your two most practical main options — back off from the relationship, or continue to guard your belongings.

As I see it, it comes down to your level of comfort with someone you feel you can’t trust. Suspicion and mistrust, even if they’re in the background, aren’t the best foundations for a healthy friendship.