Well yes and no. Some times men feel like if they have to be a "long distance" dad, then its better for everyone involved, if he just disappears. It doesnt confuse the child as much, it doesnt interfere with any possible new man in your life, he wont have to deal with the pissing contests with your boyfreinds, and he wont have to feel the pain every time he sees her and has to say goodbye, and he knows she will be spared the same pain.
Thing is, he may still want a family, so he goes and finds one elsewhere...with someone he CAN GET ALONG WITH.