Advice please? alcoholic mom

So...I guess I'm just lost, and I really want some unbiased outside opinions. I'm sorry this is long but please read it and give me your honest advice! My mom is an alcoholic. She's a totally functional alcoholic...her bills get paid, she has a full time job and a life. But she drinks vodka every single night. Her fiancé is a raging alcoholic as well, and even when he's not drinking he has always been absolutely terrible to both me and my mom. I love my mom so much and I want her in my life but I'm currently not speaking to her. My mom has hurt me in a lot of ways...said a lot of hurtful things to me, broken me apart for years...but she's also been my best friend at times, someone I could rely on. I know who she really is underneath all of this and that's what kills me. I miss her so much. She deserves so much better than this man, and to drink herself to death. But since she's in an abusive relationship, and is a slave to her alcohol, I'll never come first to her. I have every right to not want to speak to her, I can promise you that. She has really hurt me, for years on end. But I just want my mom back. I don't know what's best for me. I wish having my mom in my life without the alcohol and her abusive fiancé was a choice, but it's not. I have offered her help over and over. Please help :(