Kate my x kicked me out to be with a "friend", who had kicked her hubby out to be with mine - so I have an inkling of what you're going through. We didn't have kids, so that is different - he has kids but never sees them.

It is hard, days you wonder why you are alone, then you have days that you relish the fact you're alone and you are getting on with your life, improving yourself, getting stronger, learning from things that have happened. Don't beat yourself up over this, it does get easier.