I... don't think anything about it, as my opinion based on the scant information you've given me is probably biased due to your frustration of being in this relationship. Do you want to break up with him?
That is the key question.
Are these things you've listed out-weighing the good of this relationship?
Think hard on that question, because it is very important when considering a break-up.
Is there hope this could get better?
Perhaps if you talked about it to him, these things that bug you, he'll be understanding, obviously he finds that hitting on your friend is "just playing around" and it could very well be that.
The point is, it still makes you uncomfortable, and you should talk to him about that, also if you've got a problem with his habits, talk to him about that as well.
Find out why he is doing it (again?), problem solve, maybe suggest other potentially healthier ways of finding an out, something that would make you and him happier.
If he's not calling you, you can call him, and you're not going out anymore, once again it is a matter of communication, ask him where his priorities lie, what he wants to do with you, where the he sees the future to be going and whatnot. Try and express yourself to him about how you miss the times you two would spent time together, and be out and about having fun, just the two of you.
Really there are all sorts of other things you can try to do to preserve the relationship and hopefully bring it out of this drop you've recently experienced.
Best of luck. :)
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Danse Macabre.