My boyfriend [30M] and I [26F] had a drunken argument last night, feeling insecure and guilty

I think this is going to be long...sorry in advance.

My boyfriend and I have been together for over two years, and during that time we have very rarely fought. We are usually able to resolve conflicts calmly, which is a big thing for me as I grew up with an abusive parent.

Last night we went to a birthday party with some of his friends. In this friend group is one of his exes, who I have met a few times. They dated for about a month but have been friends for 10 years, making their relationship a little more intimate. This woman has not quite taken to me- and by that I mean she generally won't speak to me or acknowledge my presence, which is great. When she does speak to me, it's typically critical or rude.

My issue is that he does not defend me when she does this. She has had a rough year- her best friend passed away and she had a major, life changing surgery- so he is resistant to "rock the boat", so to speak, which is bullshit. We have had conversations about this many times, and he tends to brush it off or defend her, which makes me think that maybe I am just being too sensitive.

I got a tampon out of my purse last night and she got angry because she felt as though I was waving her surgery (she is no longer able to have biological children) in her face. To clarify, I wasn't waving the tampon around...she would not have noticed if she hadn't been watching me for whatever reason. She ended up leaving the room, and my boyfriend told me to just ignore her.

This upset me, since she (1) did this in front of a huge group of people and (2) he once again has let it slide. I had a few too many drinks and in the cab on the way home we got into a big argument that I feel was more one-sided, me just venting my criticisms and frustrations to him. I covered A LOT- I think this opened the floodgates to resentments I was keeping under wraps because I did not want to initiate conflict. I cried the entire time and talked about this ex, his boundaries with other exes, how I want to marry him (yeesh)...etc. On and on and on and on.

This has never happened before when I have been drinking, and I drink very rarely. I'm just humiliated and I feel bad for my boyfriend (and for the cab driver if I'm being real). I wish that I had communicated my feelings while sober, but I can't unring that bell. I guess I am writing this for reassurance, and to figure out a way to both apologize to him and to express my feelings in a constructive way.

TL;DR: While gone off the Henny last night, I yelled at my boyfriend about an ex, and another ex, and marriage prospects. Looking for a way apologize to him and constructively discuss my insecurities.