Addiction

Okay, so this may be a long story so here it goes. My now ex- finacé and I broke up about 3 weeks ago. He struggles with drug and alcohol addiction and we've been toegther for 3 years and he was cutting back and doing a little better with both. Until I got injured in May with my knee (still not able to walk) and once i got hurt it went down hill bad. He would take my car to get liquor (no license and had 2 DUI) and i couldnt control it and he would be getting high more even though we had bills to be paid and i wasnt working anymore he would keep putting them off. Getting mad more. So i decided to leave and give him space to decide what he wanted more, pills and alcohol or me. He said he would go to classes but never went and so then i finally broke it off with him and he knew I was serious about it this time. But now he said that he needs to get his life back together and he said hes going to an in-house rehab but I have no idea if hes serious about this or if I should get back toegther with him or not i miss and love him so much but I cannot deal with the lying and me having to pay for everything bill wise and him never having any money how do i know if hes serious? Or should i just leave him alone?