Insecurities in a relationship

My boyfriend is going out partying with his friends and it’s a huge house party and he didn’t invite me and I’ll just be home alone and so it’s not like if I don’t trust him I do but I don’t trust these girls and hes very vulnerable?? I’m not controlling in any matter yes hes allowed to go out and he doesn’t need to have permission from me but I just get insecure whenever he tells me he’s gonna get really hungover and high and that there will be lots of people. He’s now telling me he won’t go and I know he’s guiltripping me.On his Facebook he has almost all girl friends that are half naked and I always confront it and he’ll say their just friends from high school and he apparently knows 1,000 girls?? Also I get nervous because he never lets me use his phone or see what he’s doing he’ll hide it from me and last time I pointed it out and he said because he doesn’t want to but the other day I found out he’s a drug dealer but he still doesn’t let me see his phone after that whole fight and coming to an agreement that what he’s doing will only be temporary. Also I should mention that he has been cheated on in the past.