This sounds horrible. I am terribly sorry you are going through this.
To me, marriage is more than the ooey gooey love feelings. It's more than something to purely make me happy. The vows say, "until death do us part", not "until you stop making me happy".
Even though I say that, I know the pain you're feeling. My husband and I haven't gotten to this point, but I can understand him not wanting you. It is extremely painful. It makes me want to pull away, go out, dress up, make all the other boys jealous, but that does nothing but tare the relationship apart.
It seems like you want it to work out, if not for yourself, maybe for your children? I agree with Syrum, he is addicted to porn. In my opinion, porn is adultery. He is imagining himself with someone else and men's imaginations are vivid. I think getting the porn out of the picture, forever, is the first step. That may require counseling. The fact that he won't talk about it though, means he either doesn't see how badly it hurts you, or he is done caring about the relationship. You need to make him get serious. SHOW him your pain, SHOW him that you can't live like this forever, and make him commit to making it better. If he refuses to improve the situation by any means necessary, sadly, it might be over. I don't say that lightly. I would never get a divorce unless my husband was cheating on me, but like you said, you don't even believe he isn't cheating on you anymore.
It's true that staying and working through problems is the right thing to do, and is usually good for you children, but if it's only you working 24/7 then that is not good for you children. Not only will you have self-esteem issues, they will as well.
I hope and pray that he will come around. Good luck. Keep me updated.