I Dont Know What The Hell Im Doing Anymore

The father of my child and I were official for 3 years. Its been about a year since we broke up (he left me) And were still sexually involved and he spends the night once a week. I have a tight relationship with daughters grandma from his side. Like she still calls me and introduces me as daughter-in-law. The thing is to other families and friends close to the family Im still introduced as (his name)'s girl. Like that what everybody sees, but hes out sleeping with other women cause he gets waaay too drunk (slept with 2 more specifically), doing what he wants cause he is single now, and just doesnt want anything to do with me relationship-wise. I just feel like Im in a spot where I dont know anymore. Alot of little things say that our relationship shouldnt have ended its just Him and I dont know..