oh and btw, I have been FAR more direct than Bluefrogs on this thread and others. She's just used less words than I did! 
What she said IS harsh, but its true.
The situation here is ridiculous. A grown woman still living under the same roof as her STBX, the divorce going through, and going out with someone who will drop her like a sack of shite if his (teenage) kids even squeak.
I've explained that no decent man will be attracted to someone in the midst of all this chaos, that no woman here would be advised to carry on seeing a man that was still living in the same house as his wife... we've ALL heard that one before.
I've gently pointed out that the OP will not be taken seriously by anyone until she gets out of her marriage, and ideally spends some alone time, to help herself and her DC to get through the trauma of separation and divorce.
All this stuff in less than 4m.
OP has been posting since 2m in, the situation is the same, the advice the same.
End your marriage, invest some time in yourself, FEEL what you are living, it's OK to hurt, it's part of life, we grow from it. Take the time to sort things out for your family going forward. Know yourself, know your good points, work on any you are unhappy with. THEN look for someone that will meet YOUR needs.
ATM the terrible fear of being single is causing our friend here to prostrate herself at his feet, text him, tell him off for being an unfeeling tosser, then beg him to let her apologise. To scrabble around looking for any crumb of proof that this man gives a shit. He doesn't.
He MIGHT if the OP actually broke it off and said that he was not being supportive enough, not there for her, too evasive and distant (which is why his last couple of relationships ended).. but if history is the best indicator of future behaviour.... probably not.
This relationship is not doing her any good at all. It's not going to change, he will never change tbh, but the OP will be totally destroyed by this, she will kick herself one day when she realises what a mistake she has made.
Rest assured though..... MN will be here to build you back up OP, to help you find the YOU that got lost in the marriage, that got trampled on by Mr Nowhere Near-Goodenough.