I agree with a lot of what you said, cantstop. I still think Kurt deserves some of the blame here. Yes, he did say he knows Finn won't ever want to be with him, but that doesn't stop him from WISHING he would be. He obviously still has a huge crush on Finn. You can't just turn off feelings like that. I think that's where much of Finn's discomfort comes from.
The parents here are mostly to blame though. You don't just move in with someone after a few months when there are kids involved, especially not without a serious sit-down discussion. I can see where Finn felt blindsided - they all knew (including Kurt) and it was sprung on him and they all expected him to just get with the program.