Artist, welcome to SR.
My situation is pretty similar to yours. I was with my xgf for over 3 years and her drinking was a problem for a majority of the the relationship. I have a 14 year old son who was also very aware of the drinking. If nothing else, the relationship with my xgf has opened up some very good conversations with my son regarding boundaries, healthy relationships and alcohol and drug use.
While I can't make any decisions for you, I can encourage you to keep coming here and reading and posting. This is a great place.