I was with my ex for 5 yrs best friends for 3 yrs prior, lived with for 4 and have an amazing son that is 2. ?

We truly had a once in a life time kinda love. We were very perfect. He towards the last yr of our relationship he started becoming very depressed and drinking very heavily. our relationship completely fell apart. it finally got to the point i was depressed and very unhappy i was sick of crying and trying with somebody i did not even know any longer. I worked up the guts to leave for the sake of me and my son. That was in April. still in love with the love we had i was almost just as unhappy forcing my self to let go. well in august i meet a guy. he asked several times to take me out i always blew him off. Finally i said ok. We went out a couple times and just hit it off. Hes absolutely perfect. well should i say as from what i see. Hes literally in every way what my perfect dream guy would be like. like a dream come true. well for the last 3 months we have become rather close. We hang out often and i truly enjoy my time with him. theres just one problem. My ex, he has really tried to change, and does not overwhelm me due to respect but its very understood that hes dying with out his family and is still waiting for a miracle. Hes a great guy he just got lost in lifes journey, there's not a doubt in my mind that if i were to give it another chance we would have a fairytale love we had once. What do i do... i truly care about the new guy but to be honest until my love for ex is 100% over its pointless.. there's not a day that goes by that i dont cry and miss the way it used to be. i have tried to stop loving him its not working though. Tell me what do you think. if i never give us a chance again i fear i will regret it for the rest of my lift wondering what if. but then i fear that what if i let go a man who really seemed like something wonderful go back and try and get let down again. soooooooooooo confused....