Hmm, this is undoubtedly her way of making you jealous, and it's obviously working! She knows you're not comfortable with the whole ex thing so is using it in this situation to make you feel bad for getting drunk when she needed you. I mean, I'm sure she spoke to him, but it was deliberate so she could say this to you maybe?
Firstly, for this situation, you should just arrange some kind of night in (with no alcohol) and talk to her about her life. Apologise for being a drunken fool when she was upset. If she really does need you at the moment, give her lots of hugs and promise to always be there for her (as long as you actually will).
This ex thing is a separate issue though. Tell her you can get upset sometimes by her attitude to him. Something explaining that you get jealous but focussing on how you trust her a great deal and would never stop her from seeing him (cos i hope you're not that controlling).
Hopefully you'll both be happier once you've talked. If you're as strong as you seem then you will compromise and help each other!