Well I made that mistake too, giving with expectation of receiving. And yes I do understand what you are saying...the problem is that all you are really saying is "where is my reward?" Please believe me when I tell you that I am not judging I am just looking at my own past and seeing it being re-written in many many others' stories just like yours.
There is a spiritual approach to this that is necessary, and you don't even have to be spiritual to accomplish it, you just have to do it.
What is it you must do?
You must do the RIGHT THING.
If the right thing for you to do is move on and get divorced, then do it. If the right thing is to stick it out and try your best for the kids sake, do it.
But DON'T stick it out for the kids sake if you are not also going to love their mother "exactly the way she is"...do you see why that would not be the right thing?
I know its complicated, it hurts, and it sucks. But oh if only I could go back in time and apply what I have learned...and I only want caution and assist others the best I can so that maybe one of them (out of the hundreds of messages I have posted over the years) may escape my fate.