Long and drawn out...I am sure this isn't the most relatable place to post this, but wanted to try.…

Long and drawn out...I am sure this isn't the most relatable place to post this, but wanted to try. Thanks to a failed marriage to someone who relapsed on drugs, I ended up with a lot of debt. I tried resolving it, but after $10k of his havoc and the companies telling me there isn't anything I can do, I gave up for a while. My current SO and I are getting married in the fall, and buying a house in a year. I won't be on the mortgage since I don't have an income (I stay at home with my two little ones) plus, my credit is completely shot anyway, no big deal. But I have taken up baby sitting just to have extra cash because I feel like a bum. I really want to start repairing my credit, so I wanted to put a little bit towards some of the accounts that were in collections. My fiance has perfect credit (literally walked into a dealership and the credit guy said there was no way he was getting approved for a 3rd car since he already had 2 in his name, lo and behold the credit guy ate his words and said he had never seen that before) so I would like to get to the point where if I ever start working again, if we wanted to put something in my name, it wouldn't be an issue. How should I work towards this? Is there a certain account I should pay off first? A certain age I should start at?