Mom and boyfriend drama?

This is sort of a long, involved thing. Bear with me here:

My parents divorced when I was a year old. I never knew them together, so this is not an issue.

When I was 9 or 10, my mom remarried and had a baby, who is now my 15 year old (half) sister. About 3 years ago, my mom left my stepfather for her best friend’s husband (he left his wife/my mom’s friend). They were living together for a while, and then she couldn’t take his alcoholism and moved out. My grandmother paid her rent and most of her bills because she couldn’t afford to live alone. Now, they’ve reconciled (without even a single AA meeting, I can’t help but note) and he moved into the new house she’s been renting. My grandparents removed themselves of all financial responsibility, because my grandmother doesn’t like him. Well, no that’s not true… she loves the guy… but he promised her he wouldn’t hurt my mother and he did, so her trust is gone, yadda yadda.)

Anyway, while she was with my stepdad, he was a jerk and slept all day because he worked third shift, so my mom and I became best friends (I should also point out that my dad raised me so it wasn’t really like we ever had the typical mom/daughter thing)... but when this guy came along, she had someone else to occupy her attention and so I barely hear from her, and all the things we used to do together, I’m not even occasionally invited to. Even when we saw Tom Petty a few months ago, she offered to buy my ticket to give it to Rick. She said it was because she knew I was broke and could’ve used the money, she swears there was no other reason… I don’t believe her.

Today, I’m supposed to go to her house. She wants his kids and her kids all in the same place together for a barbecue. One of his daughters stalked my mother and tried to sabotage their relationship so he would go back to his wife (my mom’s now former best friend). I… don’t want my mom with him, I think she pays too much attention to him and not enough to my sister, and sure as hell not enough to me. She’s not a bad mother… but she didn’t get to raise me because of her drug problem, and so she was starting off fresh with my sister (she was clean by then). I love my mom and I want her to be happy, but he is obviously going to be in the picture.

I don’t like him, and I don’t like his kids because of that… especially the one who stalked my mother. She’s had to make her peace because they’re his kids and he’s forgiven his daughter, but my mom doesn’t trust her. I don’t want anything to do with the whole thing.

Sorry for dragging you all through the explanation… but… how the hell am I supposed to get through this afternoon?

I know my mom probably sounds trashy and a bad parent to you, but a life of abuse led to a life of drugs and she’s had a lot of tough breaks… she does what she can to get by