Divorce can be ugly and there will be highs and lows. If it was you, how would you feel if he wanted to walk away because things got tough?
You got to see it to the end unless something bad happend between you 2. It's easy to be there when times are good- it's being there when times are bad and sticking it out!!!!
ball is in your court......
If he is having a hard time, then be there for him and support him.