You wrote my story as it happened 20 years ago, including the infretility. so I understand everything you are going through. I did nothing to change my husband's behavior. Here are the results: daughter was first, was scared of Daddy. Son was second, this is the one that he identified with, so supported his athletics, and went to every game. (He only wanted to see one performance of the daughter's play, because why would he want to see it more?) Unfortunatley for the son, he did not spend much time playing with him. But he is fairly well adjusted, just shy like his dad.
The 3 rd child, our son, was when the ** hit the fan. He is strong willed and intelligent, and played us against each other. He wouldn't do as he was asked because he realized that there were no consistent consequences. He's in high school, and failing his classes because he doesn't like to do things that other people tell him to, so he passes his tests without studying, but fails classes because of homework. He is spoiled, and it is because we were not consistent.
The good news is that we have been to counceling this year, and we are now on the same page, working on communication, and have given the reins for success/failure over to the 16 year old son, the youngest. So, our marriage will last, our children will be independent and as successful as they desire, and in general, I am happy.
I have no suggestions, only the story of how one couple in the same situation dealt. Good luck!!