Hi and welcome Rob - I think a lot of us over the years have used some form of the bargain you struck yourself.
Nothing like that worked for me because I could always talk myself round and convince myself that it wasn't real...noone would be really hurt ....especially if I just did a bit...
I'm not sure if you posted in the Secular forum on purpose, but I'm going to assume you want a secular path to recovery. SMART Recovery is a meeting based approach that works for a lot of people, as does another method, LifeRing.
People who've used those methods maybe able to chime in and help you there, or you could Google them.
You'll read a lot about a technique called AVRT in this forum too - it's about recognising and dismissing that rationalising voice that makes it 'OK' for you to use.
It could be very useful to you.
It doesn't sound like your current living arrangements are great for you, or your son.
It doesn't mean you can't get clean and stay that way = but have you any chance of moving at all?
D