Dear Amy: For the past two years I have been in love with a wonderful woman. When we met she explained that she was good friends with a man she met 16 months before. They had a sexual relationship, but she decided it would end. However, after making this decision, they fell back into sex while on a combined family vacation.

She has always claimed that while dating me, she has not wanted to have a sexual relationship but only a friendship with him.

She speaks with him daily, sometimes sleeping over at each other’s house with her children (ages 23, 16 and 12).

Her children and he are close. Her oldest hangs out with him and his friends at parties.

I have decided to accept this relationship, even though I don’t understand it. I struggle often with my relationship with her children.

I have been in education for more than 25 years. I will sleep over on Saturday, with her children and their friends present. On the next day, he is over doing the same.

I feel confused about understanding her relationship with him and how “ours” is affecting her children. She explains that this is normal, and I am being petty. Please advise.

Relationship Confused

Relationship Confused: Let me spell this out for you. Your woman is engaged in an intimate relationship with her male friend, and whether or not it is sexual at this point, it seems to be more intimate than the one she has with you. And by the way, people don’t “fall into sex” on vacation the way you fall into the lake. Choices are being made that are explained away as accidents.

What she is proposing is something like an “open” relationship, where she can have two intimate partners. You should realize this and either get on board or get out.

As it is, she is gaslighting you by insisting that something you don’t like and don’t understand is “normal.” It might be normal for her, and she seems to be teaching her children that it is normal for them, but if you don’t like it, then that’s all that counts. Do not ask her to choose between you (she won’t) — but do leave the relationship if you don’t like its current structure.

Dear Amy: I am a graduating from high school next month. My parents have graciously given me a wonderful education at a small Catholic high school. They want to throw me a graduation party. Second semester my junior year, one of my really close friends dropped out of the school — we later found out she was pregnant and did not want to face the negative stigma that comes from being pregnant in a Catholic high school. Since then I have seen her once, at her baby shower.

I would really love to invite her to this party, since I still consider us friends, even though she hardly responds to any of my texts or Facebook messages.

My question is, what would be the etiquette surrounding this situation? She had planned on graduating with us and I don’t want to make her uncomfortable, since there will most likely be others from our school at this party. I don’t want it to seem like I am rubbing this in her face, but I would love it if she could attend.

What should I do?

Graduating

Graduating: You should invite your friend but expect that she might choose not to attend this particular party. You are right to be sensitive to what she might be thinking and feeling at this point, but her situation is already isolating and if she attended this celebration, it could help her to integrate back into this friendship group.

Be very honest with her: “I miss you! I would really love it if you could attend my graduation party. Lots of our friends will be there, and we’d all love to see you and the baby. If this is hard for you or you don’t want to come, I understand, but please know that you will always be an important part of our class.”

Dear Amy: I’m responding to the letter from “Divided Family.” I want him to know that sometimes a family estrangement is best for everyone.

It’s been 13 years since I last spoke to my Dad, and I’m better off without him and his issues.

Still Grieving

Still Grieving: I’ve also dealt with family estrangement. It is quite painful, and, unfortunately, quite common.

Amy’s column appears seven days a week at washingtonpost.com/advice. Write to Amy Dickinson at askamy@tribpub.com or Ask Amy, Chicago Tribune, TT500, 435 N. Michigan Ave., Chicago, Ill. 60611.