wow girl, sounds to me you have alot on your plate, first and foremost let me say this. I was in a relationship with a guy for 10 months just recently about 5 months in to our relationship I got this same way, i felt suicidal and like FML all the time and i constantly told him that he was the only thing that kept me sane and from killin myself, and i made him promise me he would never leave, and he did, well he lied, so let me just say this if you dont mean it dont say you will stay because lying only made it worse for me and harder for me when he left! and I know alot of people say that and things like that to show in words just how much someone means to them but seriosuly be careful with what you do, and maybe the best thing to do is talk to him about it becuase my being like that and "loosing myself" caused me to loose the one thing that has ever truly mattered to me and i think he needs to understand how you are feeling and how his actions and words are affecting you, I only wish The guy i dated would have talked to me and helped me see i was changing for the worse, and it was affecting him, but he didnt so i would probably just be upfront and honest.
and i understand about the whole first thing and how hard it is to let go of him because of that but its ok it gets easier in time if you do decide to let go i mean the guy i dated and i have been broken up for 3 months and i stilll cry but its ok everyday i get stronger! also let me say I had that "other guy" scenario to and i actually left the 10 month guy for him and it was the BIGGEST mistake of my life luckily he took me back but it put a huge strain on our relationship, dont risk a lifetime of happiness and all yalls memories for a moment of freedom and fun! I really hope i helped you see things in a different way, let me know if you need anything:)