Lovely
I just want to tell you that years from now your kids will know where the love was/is who was there wiped their bums, noses and cleaned up the sick.
Fed them went without and soothed their fevered brows, kids are not daft they will know what he has done and see the impact on you. He has damaged his relationship with his kids for ever unless he does some serious re thinking and long term work with them which will take years.
Believe me when I say my ex did the same to me and did his best for years to destroy me and leave me with nothing. My son is 15 now and 6 ft 2 and told his dad last year what a cunt he thought he was and that the 3 kids he has now are spoiled and have no manners or boundaries, and that it's his dad's fault they are like they are.
Out of the mouth of babes eh! I've told my son nothing about what really happened but he didn't need to know because his dad just carried on with the same type of behaviour during our marriage.
He sees how much money the guy has and cottoned on a long time ago that none of it ever came our way.
He loves his stepdad and the feelings mutual, I want to finish by saying it sucks I know, it's shit and hard you know, but the lessons your kids are/will learn money can't buy you and they will be better for it.
You will pass on well adjusted kids with a sense of self and love for you that he won't ever get back, this is your legacy let it warm you during the storms. 
