Meeting with "friends" but didn't mention the ex-boyfriend involved in the company, then to come home hammered, can turn into an on-going situation. Have you met the ex? You may want to ask your gf about the ex-boyfriend and what his involvement is. Not out of insecurity or jealousy, but for clarification. I've been there and know how it feels.
I hope you both work things out and support each other in sobriety.
Best wishes.