Personally, I think the father wanted to move on (as in with another relationship), didn't want to deal with three babies and a "sick" wife.
I think if he truly loved her like he stated he did, she would be living in the same house with him and the children.

And as someone else stated, if those children had grown up around her there wouldn't be a problem. They would just know that is mom.....end of story. Now that it has been almost 4 years he is using the excuse of "the kids won't be able to handle it". They would have handled it just fine if they had been with their mother from the beginning. And who's to say that Abbie would not make HUGE improvements just by having her children around her? No one knows for sure how much she can understand and comprehend. She may feel that there is nothing left to fight for since she doesn't have her husband or children anymore.

And I am as shocked and saddened as everyone else on the "not-so-nice" post. I know this is in the Dog House but it doesn't REQUIRE mean comments.