This is a relationship question. My roommate and I are both third-year graduate students at the same school (but different departments). We also went to the same school for undergrad and had some overlapping friends. At the end of undergrad, we found out we were both going to the same school for graduate school so thought it would be perfect to rent an apartment together with another friend of mine. For context, around the same time he was also dumped by his long-term girlfriend. For the longest time he refused to talk about or even acknowledge the existence of his ex-girlfriend. I wanted to respect his privacy and space, so I never brought it up. My roommate’s anxiety was through the roof for a while and all our mutual friends were really concerned for his mental health. Things mellowed out eventually and he seemed to settle into a new routine where he avoided anywhere she may be at all costs. He even got a new girlfriend and is really happy with her. This is where my problem begins.
I had a fantastic experience in undergrad and want to stay in touch with all of the people from undergrad who live in our city. Recently I decided to arrange a get-together with all of us and out of respect included both my roommate and his ex on the email just in case he wanted to come. I anticipated he wouldn’t want to, though, since he had minimal contact with just about everyone from our undergrad. Almost immediately he asked me to take him off all future communications that involved his ex, so I did and went ahead with organizing the meetup. I didn’t think anything of it until today when he revealed that he felt really shitty about the whole thing. He expressed that he felt hurt that I took him off the correspondence and not his ex and said he thought I would have had his back and picked his side in the matter. I said I was sorry and didn’t intend to make him feel that way, but I’m at a loss for what to do now. He said he won’t say I can’t be friends with his ex, but that’s how it came across to me. Does this mean I really do have to pick sides? Should I organize different meet-ups which include him and not his ex? I just don’t know how to handle this.
This is an easy one: your roommate is the one who refuses to be in the same room—or even on the same group email—with his ex. He's the one playing baby games, his ex isn't. So he's the one who gets removed from group emails, invites, excursions, orgies, whatever. The problem is his, BB, not hers—and it's certainly not yours.
But asking to be left off the invite list if she's invited is within his rights; it's a perfectly reasonable accommodation. Asking you to cut out your other friend, someone who happens to be his ex, and take her off group emails and disinvite her to events and parties is not within his rights; it's an unreasonable demand. It would be a different matter if his ex had been physically or emotionally abusive or killed his cat or slept with his mom or voted for Trump. As a general rule, you shouldn't pick sides and you shouldn't be asked to pick sides—unless the ex in question was monstrous to your friend, BB, because then your continued friendship with his monstrous ex would count as a betrayal. But that doesn't seem to be the case here. There was no violence, no emotional abuse, no reason for the kind of drama your roommate is engineering. He was in a relationship that ran its course, the end was painful (as most ends are), and now he's in a new relationship. (You might want to ask him what his inability to get over his ex says to his current.)
If he doesn't want to start losing friends—or start looking for a new roommate—he's gonna have to suck it up and learn how to be in the same room with his ex.