when will it end?

I have been with my husband for six years and married for five. We have a fourteen year old son from a previous marriage and a five year old together. My husband has an addictive personality and would go all the way wether its cocaine, pain pills, muscle relaxers, codeine cough medicine and now adhd medications that he steals from our five year old. It doesn't phase him that he has been in rehab twice in 5 years and worked with two therapists and one pschyiatrist. It is a constant problem. When he goes all out we see the monster he becomes. Last saturday, he took 17 vyvanese, 40 ritalin 4 ambien and 3 concerta. In two days, he spent nearly 800.00 at strip clubs. He tries to hide his addiction, but he couldn't hide it last saturday. What started the fight was me bringing home a drug test kit and following him around to collect the urine sample. For hours he paced through the house hoping I would forget. Finally he peed in the cup and it tested positive for amphetamines. Then the monster came out. When he isn't high, he is the most noncomfrontational person I know. He is a pussycat. Not that night. In front of my five year old he called me a slut and a whore. He said he wishes he would have picked his friends over me since his friends say I am a bitch. He also said I don't anything to better myself or to take care of myself and he would cheat on me if he found someone better looking. Now remember this is in front of my five year old. He then exclaimed he was leaving and taking HIS son. The next part we were in the driveway struggling over a five year old. He had his arms and was pulling and I had him around the waist. I would die before letting this high monster take my son in a car.I was able to get everyone in the house by convincing my husband that he needed to call him mom before showing up. This is around midnight. At this point he is hallucinating and talking to people who weren't there. I finally got him to try to sleep it off. The next day the waterworks began. He has a load of self pity, he hit rock bottom, he doesn't remember whathe did or said. And of course beg for forgiveness. I can't trust him let alone forgive him. Every story he tells me is its the last time and he will be better than ever. All stories for me to leave him alone. I am really lost. I am so embarassed to tell anyone I know about this. His problems have become my problems.