Boyfriend going out...

My bf and I have been together for 3 1/2 years. Recently in Nov. 2016 we moved out together , going well. Now recently he has been going out a lot more with his friends and coworkers. We have agure about this so much why he can go out and have fun to the bars/clubs with his friends/coworkers. and I can't. Well I work Pet ER and I work the swing shifts and weekends so obviously I can't have fun with him but when I have my days off I asked him if we can go out to bars and clubs but he doesn't want to go with me. I mention to him not so guys go out with there friends knowing they have a gf of there own. all his friends are SINGLE! I am nervous that his friends will end up saying something to him that he will regret. I trust but i don't trust his friends at all. Ugh! This sucks and makes me furious. He lets me know he is going out but still it sucks.