soon to be ex is dating but won't help out with his kids

I found out my soon to be ex is havering sex and is dating other woman and we are not leagully divorse yet I found condoms and and other stuff and to find out he rather have a f..., buddy take out and don't give me any money tords the kids that are 2.5 and 3.5  he has a full time job and Iam on Ssdi and I also get help from the state money once s month  I saw what he had been spending and he does a lot of with atm with draws 40 here 80 here 100 here and on top of the fee s that are added on from a non checking account like the Casinos  and buy unessary stuff I had to move back in with my parents for finance reasons with my two kids and my two dogs not happy about but it was a bad citation when the police had to come to the house to help me be escorted out  of our house the divorse date with the court is not till September 8 at 10 am the most he had given was 123.00 dollors since I left the house may 11 and I find out he is spending money on woman and not his two young kids the woman are more important than his kids and he is very selfish