I'm 14 and I dont know who to live with.. Mom with boyfriend of 5 years or Dad with stepmom and brother?

Mom and boyfriend are going to buy a house together (not getting married) I cant stand the guy he brings his 2 kids over that have no respect for the house and when I trying talking to them they ignore me they go into my room read my diary they even took fake spraypaint snow and covered all my mirrors with it they have no manners and I hate them and the boyfrined spends everynight here even when he has a nice little house himself, I mean gosh you guys cant spend 5 mins away from each other!!! Please help I'm really confused -Angry