Well some people just aren't worth the effort. He may be one of them.
I've come to the realisation that my STBXW actually didn't understand or mean her wedding vows, and I'm still annoyed with myself that I believed a word she ever said to me.
I will forever be puzzled on how some people can walk down the aisle and then a short time afterwards seem to forget what they said on that day, the promises they made.
But some people just can't keep their word, some just can't keep their trousers up, some are too self centered to do anything other than what is right for just them at whatever time they choose. And if they bail this early, then you sure as hell don't want them around when there are real pressures like kids and serious illness to deal with.
The more time I spend in this life, the more I come to realise that the only person you can really depend on is yourself. EVERYONE else will let you down, hurt you, abandon you or upset you. So spend time on making yourself into someone you like.
Reality is that which, if you don't believe in it, doesn't go away.