Do I invite the roommate to my birthday celebration or not?

Some of you are familiar with the back story here, but here’s a brief overview:

I’ve known her for 15 years and we were roommates about 10 years ago. We lived in different cities for quite some time and lost touch, but got back in touch over a year ago. I ended up taking a job in the city she lives in and we decided to be roommates. I thought it would be fun to rekindle our friendship and our previous roommate experience was great, so I was excited. Things went downhill very quickly when she moved her boyfriend in without talking to me about it or offering for him to share in the bills. He was living here 6 months before I finally had enough. There have been other issues, too, that I don’t want to rehash. Since then, the boyfriend issue has since been addressed, ground rules have been laid, and he is gone most of the time… but now, there is a lot of resentment between us and the friendship is pretty much dissolved, on my end at least. Besides the animosity and tension between us and in the home, we really have nothing in common and there’s really nothing that she has to offer me in the way of a friendship that makes me want to work on it. I get the feeling she wants to try to work things out and maintain a friendship, but I have no interest anymore.

Back story over…

So now, here’s my dilemma. My birthday is coming up in a month and I’ve been talking to some of my close girlfriends about doing a girls night out. I don’t know if I should invite the roommate or not.

On one hand, I feel obligated. She is my roommate and we have known each other forever. It would be awkward to not invite her. I’m pretty sure she’ll ask me what my plans are for my birthday pretty soon. I sort of feel like I should “be the bigger person” and put the invitation out there and let her decide.

On the other hand, I don’t care and don’t want her there. At all. It’s not just because I’m bitter, but that’s a big part of it. A lot of it has to do with the fact that I’m about 90% sure she’d ruin the night. You see, she’s one of those people who can find a way to turn any fun group event into being about her. She will typically find something to get upset about and she goes into what I call “poopy pants” mode. She shuts down, gets quiet and awkward, snaps at people, and sometimes just disappears. As in, will literally walk away from the setting and vanish for sometimes hours. I’m not dealing with this on my birthday from a grown woman. I’ve seen this happen several times and it’s very embarrassing. Additionally, all the girls who are coming know what’s been going on between us, so that could be awkward on another level :/

So, what would be the most tactful way to handle this situation?

Help!