My dad is a cheater!!!!?

about a month and a half ago my stepmum discovered my dad was having an affair with a lady who has always been nothing but trouble and doesnt even care about her own kids. anyway. he told us he broke it off wih her and he hated her because she was black mailing him but then a week later he "accidently" said he still had feelings for her,then denied it,another week later my stepmum received msgs from this woman that my dad had sent to her saying hes only going to my stepmums house because she threaten to kill herself and my sister (not true) and said us girls have never liked her so we will accept this woman in our lives (also not true)he denied all of that too, then tonight he was caught red handed by my stepmum at a festival cuddling "her". hes now ignoring us kids,i havent spoken to him in 3 weeks because he wont talk to me. i have a baby and one on the way. i have always been close to my dad and now dont know if i will ever see him again. we cant find him...any advice?