Wow, and you love her kids? <---this here shows how much value you have. You love children that you didn't attribute to giving birth too. She doesn't see the value in that??...
Holy crap man she will be Hard PRESSED to find a man willing to put up with her and love her children like you are doing man...
The way I see it she doesn't deserve you. I agree with what everybody else in this topic is saying...Go no contact immediately, start dating and spinning other plates.
I bet dollars to dimes she will regret not giving your relationship attention...