EMS may be hard to get into, but have you thought about trying to work in a rehab type career? I've seen multiple instances of people with prior addictions turning it around to help others in that spot. If those patients are something you are passionate about, it may be worth your time to pursue a career down that path.
I agree... especially with a good attitude. OP seems to have a good attitude.
I'd start with a GED. That is going to help you in so many ways, EMS and otherwise.
If you are willing to relocate, you might stand a better chance getting hired in EMS. If you can get your GED, do your class, get certified, and have kept your nose clean through that, develop that solid reference from your EMT program, and then you find an employer who doesn't have 100 applicants for every position (which is why you might have o move), you could get your chance to establish your reputation. But I don't know if your new wife would be stoked on moving to some desert town in Nevada...
I think Jim37s point that a degree, even an associates degree, is going to both make you stand out and offset your record. It can be in whatever you want... AAS in EMS, AS in Biology, AA in Art, whatever engages you. Remember, a degree says much about your ability to think, commit and finish something as it does about the knowledge learned. Community college is pretty inexpensive especially with financial aid. But first things first: GED.
If you make your record look like this:
2016 BAD STUFF
2018 GED
2019 EMT
2021 Associates Degree
All of a sudden you have established a track record of defined achievement that points 100% away from BAD STUFF. That is part of what you need to earn a chance at good opportunity... in EMS... or anything else. That is how you start opening the doors that you shut.
Remember one other thing: most of EMS isn't emergencies and life saving... it is caring for people and solving problems... healthcare is actually not glamorous most of the time, even EMS.
StCEMT's mention of caring for people a different way that uses your individual experience as a tool is spot on. Addiction treatment and rehab is definitely a part of healthcare you'd have an easier time working into. Plenty of ResCare Technician and even Counselor positions only require a GED. They are more understanding of a record if you've been on the right track since (ie 3 years+). If you throw in some community college Psychology, Sociology, Biology classes, that's a huge plus on a Tech resume and sets you up to go the Counselor route. Also, you won't have to move to South Dakota or the high Nevada desert for a job... plenty around cities and nice climates.
Keep us posted.