Whats it all mean wen theres no intimacy?

I've known my baby momma for 5 yrs.we were in a relationship 4 out of the 5. We used to have sex like animals.lol but towards the end I could tell things were falling off.she was less active and less intimate wen we had sex.now I have a nasty mind.I love sex and I kno she does to.anyway immediately after she left me I caught her with another guy.whombshe slept with.1 month after our 4 yr relationship was over.I understand we weren't together at the time but I'm sure yall can see how that would make anyone feel.to see ur gf of 4 yrs yet intimate with sum1 else that quickly.but it didn't stop there.now we did have sex once back in February but it was baaad.and I think it was pity sex for me seeing her with that guy.now as this yr unfolded I found out she went and got a new bf.(different guy) and found out she was sleeping with him and a WHOLE NOTHER GUY.I was heartbroken.but wat hurt me the most that she and I were around each other everyday.sumtimes is even spend the night.but no sex.I asked her why she don't me.our sex life basically fell off to the point where as she put it "new Dick was required" my self esteem took a huge dive.and for a while I felt like less of a man.until I started sleeping with other women and gettin different answers.I felt a lot better after that.but I asked my ex last night why again and she said "you don't turn me on" wat should I do I don't wanna give up on a family bc of sex.but I'm only 22 yrs old.so I can't go without any longer