sorry, id have to say, maybe proceed with great caution, if that is what you decide to do. personally i think maybe it would be good if you could continue to keep your distance while you continue to watch his action concerning his recovery. i was told that an addict can be anybody they want to be for a while, not saying this is the case though, your guy sounds great.
you said he found himself in some trouble with dui's and went to rehab? well that kind of cause an alarm in my mind because in the community of addicts, i've been told that rehab helps to escape consequences of illegal actions. i've tired it myself, it did help with the legal side but didnt' do much for my sobriety. i went to rehab with an underlined motive, hope thats not the case.
you also said you thought he had his head on while using, but imo, i don't know if buying prostitutes while high is something functional people do. i'm not sure though so don't take my word for it. sounds like he has money to splurge but have you thought about what would it be like if the money ran out because of his functional drug use? i sure hope i'm out of line here, its just that you've only know him 5 months and he's only been clean for what he says is 9 months and i care.
i married my abf for some of the same reasons as you, it took me 21 yrs to figure out, besides our 2 kids together, that was one of the biggest mistakes i've ever made. i pray that things work out well for you guys. i know that it is possible. i've been clean for 7yrs now and before relapse, i was clean for 9yrs. relapse is so common and very hard to avoid for an addict, it takes a lot of work. even now, i couldn't promised that it won't ever happen again. all i can say is that i promise to do my best not to.
ps. i re read your post and realize that your bf's childhood sounds a lot like my ah. after yrs of knowing him and his family, i found out that a lot of what he told me, was his side of the story, one he used to reel me into his world. i found out that there is always 3 sides to every story, his side, my side and the truth. hope this is not the case too. if i'm being harsh, i'm sorry. i care so much and i feel that i've suffered so that you don't have to.