What do you do when your mom constantly puts her boyfriend before you?

My mom has been dating this guy for a little over a year and he's never had a family so he doesn't know what it's like to deal with kids or teenagers, so whenever my sister and I start to bicker or i'm in a pissy mood he threatens to leave and my mom gets super mad at my sister and I. He also drinks a lot, he had an entire bottle of vodka and a couple beers, a gl of wine or two, in front of me and my 11 year-old sister. But the real problem is on Christmas eve she wouldn't pick us up at the airport because she was at a party with him. She spends the night away a lot at his house. I don't know weather to confront her about it or just let her live whatever lifestyle she wants. Any Advise?