One thing to keep in mind is that a lot of people act differently depending who they're with. For example, when I'm around my peers, I have something of a potty mouth, but when I'm with my family, I speak a lot more formally. There are things I would do in front of my friends that I wouldn't do in front of my family, too. I think all of us are like this.
Your man may be like this, too. It could be that he's not fake when he's around you, but that he's relaxed enough to be himself and not feel like he has to put on the tough guy act like he does with his other friends... Your fears may be valid, too, though. There's only one way you're really going to find out: talk to him about it, as calmly as you can, without seeming like you're accusing (because that will just put him on the defensive.)
I'm sorry you have to deal with this stress.

Remember to listen to what he has to say about this, and trust your own instincts as you listen to him, then do what's best for
you.
Hoping you find some sleep tonight. Take care... *hugs*