My ex-husband, a compulsive liar, is dating a friend of an acquaintance of mine. My ex and I are on speaking terms because we have two daughters together. He is unreliable and immature, and he lies about everything—including his sexuality. (He’s definitely bi on the down low.) Do you think I should tell my acquaintance so she can warn the woman my ex is dating?

Only if you have scrubbed the facts down to their shiny-clean core and are clear about how much of your concern is a lingering outrage at being deceived. Once you skim those residual feelings away, cut out other worthless distractions. Ask yourself: “What is the source of my information?” If it is an explanation cobbled from your feelings and bits of conversations from friends who agree with you because they fear confrontation, don’t believe it wholeheartedly. Instead, understand that your interpretation reveals more about your fears about who you really are (naive, perhaps?) than it does about your ex-husband.

You must also accept that some people do change. If your ex-husband committed himself, post-divorce, to personal growth plus the study and practice of genuine love, he is not the man you knew. Yes, it’s rare that this would be the case, but leaving that door open proves that your brain is not all-knowing after all. It also shows your faith in humanity and faith in your own ability to become a new creation.

So, should you air the dirty laundry of the man you once professed to love? If your acquaintance asks for your opinion, say your marriage taught you to not to invest your trust in someone else so completely that you fail to listen to or trust yourself. And that the man you married is not someone you would recommend to a friend, ever, but her gal pal’s experience might be different. You can also say, since it’s true, that you and your ex failed to ever arrive at an agreement of what telling the truth actually means.

My ex-wife has a key to my home because, when I have been out of town, she has needed to pick up things our kids forgot at my place. I am getting remarried, and my fiancée is uncomfortable with the way my ex-wife enters our home without notice. It is not the same home I had while married. The other day, my fiancée was in the shower and my ex came into the house, left a few things and exited without relocking the front door. My fiancée could hear someone in the house, but did not know who it was. She is furious now. I know I can just ask for the key, but I have worked hard to establish a good relationship with my ex and I want to ensure that this does not blow up, since she tends to be passive-aggressive.

Your fear of facing your ex-wife’s passive-aggressive behavior cows you into allowing her the run of your home? Wow.

Sit your kids down for a family meeting. Explain that your ex-wife is important because she is their mother, but that she cannot enter your home without explicit permission from you or your new wife. If your children are mature and have house keys, explain that the key should never be left with your ex-wife. Then call a locksmith.

Afterward, tell your ex that you have new locks. Tell her that she will not receive a key. Promise you will work with her to ensure life is organized so a key is not necessary for her. Then express sincere gratitude for her flexibility and support over the years. If she acts out, don’t overreact. She’s just being herself.