Ok need advise

I am 28 and I have polycystic ovaries syndrome I've been with my boyfriend for 6 years we have had one 41 week pregnancy that ended in a stillborn and also had a 15 week pregnancy that ended in an abortion do to health issues my boyfriend has become addicted to opiates and alcohol and I quite frankly have giving up on our relationship except during my fertile days. Lately someone from my past has caught my attention it's a guy I grew up with anyhow he's a straightforward sober guy who has the same dreams as me and wants the same things out of life the guy I'm currently with is selfish or drug addict and only cares about getting high and drunk it has been this way for almost 2 years and I just don't want to put up with it but yet I feel like I can't live without him what should I do should I let go and move on with my life or should I stay in his current relationship that I'm in