First of all, let’s talk about you being “fine” with your parents’ divorce after 40 years of marriage. Are you sure you’re really okay with it? I mean, more power to you if you are, but if it were me, and my parents, who have been married almost 38 years, got divorced, I think it would take me more than a year to truly adjust to the new state of things, including Mom having a new boyfriend. In fact, I’d probably be pretty weirded out by it, to be honest. And I suspect you may have similar feelings, if only because if this guy is “extremely nice,” as you say, why would you be so concerned about deciding the terms of contact you want to have with him? Why would it bother you so much when your mom shows up with him? If we were talking about, let’s say you sister instead of your mother, would it really be all that strange if she showed up to an event or special occasion with her significant other in tow? Isn’t it just expected that adults in relationships usually bring their “plus ones” to socials outings?
But if your mother is literally showing up at your doorstep unannounced with her new boyfriend, that’s something else, isn’t it? And it makes me wonder if she’s doing that because she feels it’s the only way you’d ever meet her new guy, in which case, that says something about your family dynamics post-divorce as well. And if she can feel how resistant you are to the sudden change in your family and to the idea of her dating a new man, it’s no wonder she might not feel welcomed to share news with you or your siblings of a potential marriage. And that’s a shame. Because whatever went on in her marriage to your dad is between them. They’ve finished raising you and your siblings, and obviously decided that they weren’t getting enough from each other anymore to be happy. For all you know, their divorce was a long time coming. And now it seems your mother has found happiness after what was likely a painful experience. That’s a good thing. That’s a very good thing. To find someone at her age — someone “extremely nice” — she thinks she might like to spend the last act of her life with after perhaps years of unhappiness with someone else (you don’t just end a 40 year marriage because you had a rough couple of months) is a very special thing indeed.
I guess what I’m saying is, do what you need to do to find — or at least fake — happiness for her. Go to therapy if that will help. Talk it out with your siblings if that will bring a sense of closure. Mourn the passing of time and grieve over the death of your parents’ marriage, and then pull yourself together and be happy for your mom, because I’m guessing she poured herself into being a good wife and a good mother for many, many years — making lots of personal sacrifices along the way to raise happy children, and now it’s her turn to do something for herself. So, try to find some place in your heart that feels glad she’s found a nice guy who makes her feel good. Try to get to know this man; he doesn’t have to be a father figure — you don’t need one — but maybe he can be a friend eventually. And feel grateful that the woman you love so much who has done a lot for you is in a good place right now — at a time that had potential to not be so good.
As for telling your father about your mom’s possible remarriage, I personally think you should, if only because it’s pretty big news to keep secret indefinitely. But don’t do it to spite your mother. Tell your father only after you’ve given yourself time to adjust to the news and to find that bit of happiness I hope you’re able to tap into for your mom. If there’s a chance your mother’s remarriage could change her divorce settlement, then of course, you father has a right to know — legally and morally, and you’d be saving your mother a lot of trouble if you — or one of your siblings — convinced her to tell your him herself. I really do think it will be easier for her to open up if she feels she has the support and blessing of her children. So, dig deep if you have to, but know that your mom finding the love of a good man is definitely worth celebrating, even if it means pushing some of your own baggage aside.
*If you have a relationship/dating question I can help answer, send me your letters at firstname.lastname@example.org.