Welcome to SR!
I'm a recovering crack addict, and I left my XABF, who continued to do crack. He was the third XABF, all of whom had substance abuse issues, and I was as addicted to them as I was to the crack. That part of it is called codependence, and SR has helped me, a LOT, on working a recovery for my codependence.
To answer your question, yes, crack does make a lot of men want sex. It's how XABF encouraged me to try it in the first place - "oh, sex is awesome on crack!" Yeah, well he forgot the part about how it makes some men unable to perform, yet they still want it.
I went from being a highly certified RN to stealing drugs from my place of employment, two days after I smoked crack the first time. I eventually ended up on the streets, prostituting myself for crack.
HOWEVER, I also have over 3-1/2 years in recovery, so yes, we can and do recover, but for most of us, it takes a lot of harsh consequences to get to that point. Mine included jail.
No one, no matter how much they love someone, can get an A (addict) to quit, unless they really want it. However, when I was left in jail, I did get enough clean time to at least get my head sort of straightened out, and will forever be grateful to my family for leaving me there. I dug the pit of despair I was in, and it was up to me to get myself out of it. That makes my recovery even more precious.
As for XABF#3, he continued to smoke crack and do whatever else came along. He died a year ago. I am sad, but I also know that my leaving him was best for both of us. I couldn't have saved him and he was okay with bringing me back down to the life I'd worked so hard to get out of.
Please read "Codependent No More" by Melodie Beatty. I should have learned after the first XABF that I was a codie, but I didn't. I've spent more than half of my 49 years in really, really dysfunctional relationships.
As for his relationship with this other woman? Don't even go there. You don't think like an A does, and when we're using, we're all about getting what we want...whether it's someone to let us do our thing and not nag us, or sex, money, dope....whatever. You will never understand his thinking, unless you're an A. It's an exercise in futility.
Hugs and prayers,
Amy