Annie Lane, syndicated columnist

Dear Annie: I am a single mom with two kids, who are now adults. My husband is also divorced. He and his ex-wife, “Tricia,” have a 12-year-old son.

The reason they divorced is that Tricia was caught cheating. But by my mother-in-law’s telling, Tricia only cheated because of my husband’s own wrongdoings. My mother-in-law always protects Tricia like that: shows her sympathy and insists that she is still part of the family since she’s the mother of her first grandson. His other family members don’t like Tricia because of what she did.

My mother-in-law and the ex are still good friends, and she always wants her to be involved in our lives.

I’m writing now because my husband’s son is staying with us for a vacation. His birthday is coming up, and we’re having a party for him. My mother-in-law wants Tricia to join us with the rest of her family. I feel hurt because it seems like my mother-in-law doesn’t care about what I feel.

My husband also doesn’t seem to care about my situation, even though I told him that I feel offended most of the time for his mother’s actions. He will only look at me and say, “You should have known my mom would act this way.” — Feeling Jealous

Dear Feeling Jealous: Inviting Tricia to her son’s 13th birthday party is the gracious thing to do (assuming things are amicable enough between your husband and her). Dig deep within yourself to find the fortitude. Set your feelings aside for two hours.

Beyond the birthday party, though, it sounds as though your main problem isn’t with the ex-wife but with your mother-in-law. You’re afraid she’s rejecting you. Rather than pouring all your thought and energy into trying to make her like you more than his ex, let it go. The relationship that matters most here is your marriage. Work on opening up communication with your husband, potentially attending a few sessions of marriage counseling together, so you can work past insecurities and develop the skills to talk to each other. When you can fully appreciate that your husband loves you and has chosen you, you won’t be so concerned with what his mother thinks.

Dear Annie: I just don’t know what to do. My husband is always talking and texting young girls. He’s even been slapping our granddaughter on the behind and trying to make our younger granddaughter kiss him on the lips. My daughter and I both told him this behavior is unacceptable. He is no longer allowed around any of my grandchildren.

I told him that I wanted a divorce, and he said that he didn’t care what I wanted. He said that he was not going anywhere.

Recently, he was also being touchy with some of the ladies where we live. Finally, I told him that I had talked to a lawyer. If he didn’t straighten up, then I would sign papers and he’d be out.

So far, he has been behaving himself. But I can never trust him again. And now, on top of this, I have people telling me that he is digging in trash cans for cigarette butts. What should I do? — Disgraced, Disgusted

Dear Disgraced: I’m so sorry you’re in this awful situation. From your letter, it sounds like this has been an abrupt personality shift. That could indicate a serious health problem such as dementia, which can damage parts of the brain that impact sexual behavior. You and your husband should consult his doctor, who can diagnose any potential health issues or refer you to a specialist who can better help.

Editor’s note: “Ask Me Anything: A Year of Advice From Dear Annie” is out now! Annie Lane’s debut book — featuring favorite columns on love, friendship, family and etiquette — is available as a paperback and e-book. Visit http://www.creatorspublishing.com for more information. Send your questions for Annie Lane to dearannie@creators.com.