Scared to ask SO if I can go out Friday night..

So a little history on our relationship.. we have been dating going on 4 months now and have known each other 5. When we first met, I admit I was promiscuous and was talking to a lot of guys.. but I was single and I'm aloud to do that when I'm single. Since the day that I met him, I haven't slept with anyone else. But talking to other guys.. well I talked to another guy until we started dating.. I honestly lost interest in any other guy as I'm happy with my boyfriend!! But he found texts early on of me talking to this guy. But I had already stopped talking to the guy by the time he found the texts. My boyfriend went through my phone the first week we knew eachother,(before dating) when I fell asleep and that's how he knows I had been talking to other guys a lot before we met. Well he knows my best friend cheats on her boyfriend of a few years. (I don't agree with it but I'm not going to tattle on her) and my other friend has slept with men for money, he knows this by going through my phone so much. Me on the other hand have nothing to hide! I'm not interested in talking to other guys, my boyfriend makes me happy!! But he HATES when I hang out with my girl friends. I don't talk to my other gf as much any more since she started sleeping with men for money because that lifestyle just doesn't suite mine. So really I have only just kept communication with my best friend who cheats on her boyfriend.. but every time I hang out with her my boyfriend and I fight. He says she's a whore and a nasty slut. He thinks just because she's a cheater that I will be a cheater too. My gf and I want to get drinks Friday at small bar in town, which is honestly mostly old people, not a college hangout spot at all. All those spots are downtown. But I'm so scared to ask him if he cares if I go. I know he's going to get mad and I know it's going to cause a fight but honestly I've been spending all my time with him and I want to see my friend! Yes, I talked to another guy until we started dating but I honestly lost interest in him the moment I met my boyfriend. I haven't done anything else like cheating or anything to him. I've been faithful since we started officially dating. But other than my friends being promiscuous, he has no other reason to be mad. Am I in the wrong or is he controlling? How would you handle this situation because I'm not going out to get drunk and fuck dudes, which he will think that's what I will be doing. Can you please give advise, honest advise! It's okay if you think I'm in the wrong too, I just need advice.