I have three of them and it is very difficult. I also get very little help....actually I get no help with parenting. He calls them maybe once a week and sees them once every couple months for a couple hours....he has no desire to do any real parenting. I asked him once in a text if he even wanted me to let him know when I had issues with the kids. His response was...you can pull me in and I'll tell you what I think. I did try that a couple time though....got no response at all...asshole.
My kids have each handled everything so differently, so I had to handle things differently with each one of them. My youngest was the only one who got angry with me, and who I know at the time also blamed me for his dad leaving. He is also the one who has always tried so hard for his dad's approval. Because of this, I knew why he was taking his anger out on me. I was the safe one, and even though it was hard, I didn't take it personally. He could be mad at me and he knew I would still be there for him. After some time that anger directed at me did stop. He even told me one day when he caught me crying, that one day dad would regret leaving and when he came back I would be the one telling him that I don't want him anymore. Love that kid..
The other two have directed all of their anger at their dad which is hard also, because quite frankly it's pretty hard to try and defend/explain that asshole in any way. Mostly I just say "your dad is going through something, but I know that he does love you".... Pisses me off cause you shouldn't have to try and convince your kids that their dad really does love them!
The one thing that I think that has really help all of them is that I always try to be honest with them. They ask....I answer. I also try very hard not to speak bad about the asshole in front of them. I don't always succeed in that but I try, and when I fail, I always apologize to them and let them know I shouldn't have said that and it was done out of anger.
It has been almost a year now since he blew up our lives, and the relationship I have with all three of them has gotten so much stronger and I cherish that. With having to deal with their dad walking out on all of us....I wouldn't say that has gotten better so much as they have just gotten use to it.