I'm not really sure what you are waiting for him to do.
You know what he's been doing; you don't know why. But it doesn't matter why.
If it was anything sensible or decent, he would have told you.
He hasn't explained anything and he's not going to. The more you say 'consider your next move, buster' the more he is thinking in a bemused manner to himself, 'what? I'm not going to confess or anything if that's what she's waiting for! Ho hum...'
and therefore he naturally presumes that you are going to KEEP waiting, because he's certainly not going to do anything. You're sticking around at the moment. He thinks you will continue to.
If he gave a JOT about you or the marriage or the baby, I mean the real him, not just the him who feels pressured to please his parents - he would have acted very differently over this. But he's behaving like a teenager caught red handed.
He WANTS it to end, he wants you to ditch him. He can't allow himself to do the right thing. He's trying desperately to escape from an imminent marriage. And he can't help himself.
I just don't understand what you're waiting for - it's so unlikely he will suddenly pull something out of the bag that explains everything in a genuine and grown up manner.
You're testing him on something when he's already failed it, patently failed, failed to answer at all, and it's like with a child when you threaten to cancel their party until you get the truth, but they know you won't cancel it whatever they do.
He thinks he has you. You're still there! Why are you still there?! 
He really only cares about his own backside. What is your plan for getting rid of this jerk?