I understand this feeling too well! The father of my children keeps making half attempts at being their dad but always cancels or has some stupid reason not to come and see them. He then started making me feel like the one to blame, saying he had no money so if he were to see them it would have to be because I drove them to him. Which I started to do for a while, but then I still see him smoking and going out drinking. He works full time and I work part time and I pay for nursery just so I can work, he earns way more than me yet somehow was making me feel like I had to use my petrol to drive the kids to see him when I have less money than he does! In the end I told him he had to make more effort and at least meet me half way (so to speak) one week he comes to my house the next I drive them to his. Needless to say he didn't make effort to come to mine so I stopped driving them to his. It made me feel so bad and made me feel like I was somehow to blame for my kids not seeing their dad, but he makes no effort at all and now I realise he was just waiting for me to say I won't drive them any more so that he can not see them but feel like it's not his own fault. I've told him he can come and see them any time or take them out, I even don't work Wednesdays so they aren't in nursery as I know it's his day off and told him he can come and have them every Wednesday but he doesn't.
Yet I still feel guilty because I know my kids could see their dad if I just drove them to him. But bottom line is that he doesn't really want to see them otherwise he would make an effort. Some dads would move heaven and earth to see their kids but my kids dad won't even get on a train for a 40 min journey. So I figure they don't need a father who doesn't really want them, they would end up picking up on the fact that he didn't really want to see them and they don't need a father like that in their lives. If he ever wants to make an effort I won't stop him but all this still makes me feel guilty when I see other kids playing with their dads and feel I should have maybe chose a better father for my children.