Wow. I'm glad you didn't have to see all this until now as an adult & yet I'm sorry you're going through this at all. Both my parents are addicts, well "recovered addicts", so I grew up watching it & pretty much caring for myself. My husband is also a "recovered addict/ alcoholic/gambling addict" . So I have dealt with it a lot in other members of my family.
With my parents, well as an adult with children I never lived with them, so I told them they couldn't come around my kids unless they got sober. Eventually they moved to another state and got clean (especially hard for my mother who had been in & out of rehabs my whole life & even o.d.ed a few times, once sending her into a comma). A year later we moved about an 1hr &1/2 away from them and since then have had a great relationship. (mind you it's only been about 2 & 1/2 yrs of sobriety for them at this point) Any way, with them I came to the realization that they would only get clean if it was what they truly wanted & they would have to hit rock bottom 1st, but that I didn't have to suffer from it, I didn't have to enable them, & I didn't have to subject my kids to it.
With my husband, he had been clean from drugs for a long time before I even met him. He hide the extent of his gambling & drinking problems at 1st & when they all came to light we had already had one of our kids. After we moved (out of Las Vegas none the less) his gambling stopped (even though we live down the street from a river boat casino), but his drinking didn't. He started to try & hide it again, but I knew all his tricks at that point ( we have been together almost 5yrs now). Anyway I kicked him out & told him if he didn't stop drinking I wanted a divorce & I would ask the courts for him to only have supervised visitations with our girls. (he was a violent drunk). He sobered up that day & has been sober for 1yr now.
If you don't trust him, the you probably have good reason. Addicts are great liars. Sometimes it's necessary to "baby" someone with addiction issues, especially if rehab hasn't worked, but they seem to typically find ways around it....at least in my experiences. I'd give him a shot, but be cautious. I wouldn't give up on him just yet, but be careful not to become an enabler.