Been watchin' this one...

Having been through the big split 11 years ago, which ended an 18 year marriage (no kids), I can agree on the pain, and the advice on the real need to get out of the self-pity trap!

This "ex-sex" thing always confuses me...
When I out of "hell", there was absolutely no way I was going back for "candy". The very thought was repulsive. It was over on every level.

Bluntly, if you can still happily boink, (especially for a woman), then the relationship can't be over. But it definately needs work at some superficial level.

Having the 2 daughters and wanting to be involved with them makes you the best option for "Dad", which I'm sure their mother recognizes.

So if you're still there as Dad, and still there in the sack, it sounds like the deeper needs are being accepted between the 2 of you, and it's only on the surface that your issues of incompatibilty occur.

You 2 sound like prime candidates for benefitting from outside professional counsel. This co-dependancy thing can be beat.

And as felt (again)the cost of selfishness, will it change you?
One day at a time.