Have two kids 9 boy n 8girl goin threw a ugly custody fight its complcated ill do my best 2keep it brief?

My ex had a bad habbit of takin our kids around his multiple girlfriends which made our kids upset due to dad n girl make out sessions in front of them wen i asked dad he denied n say im lieyin n dad visits i ended went bak to court n got a npte statin his lawyer ask for extension for the 730 eval dad requested (claims im crazy) dad came around n we talked it out so i thought i let the kids go with him for the weeken well sat nite he returned kids this wat my kids said my daughter'mom i saw daddy naked with nancy'son 'yeah mom daddy yelled at us to go bak n watch a movie n to take care pf kayla' (kayla5yrsold nancy daughter) n then they both said 'mom daddy was w/all three in one day' try2 imagine whats goin threw my mind i did my best to explaine n im goin to have them se a therapist i have not allowed them to visit since now i know my son misses his dad alot i find him cryin or in a daze it breaks me i let my kids call n they do he never calls bak recently my son wrote a poem about his dad n its mind blowin i keep tryin to contact dad but nothin plz dont know wat to do with my son my daughter says she hates him but she dnt she hides her feelings how can i make him (dad) see how much our kids r hurtin ? Wat do i do im so conffused