Someone out there help me, we had fights coz he is too close to his ex g/f who is a swinger(many sex partners), i was too scared for my life but this pissed him off leading to regular fights. His ex new about every single fight we had. He canceled a trip 4 days before we traveled and now i just found out that he already has a new g/f 3 weeks earlier than our trip was intended. Meanwhile he insists he is single but wont see me as he is just too busy. He calls me the love of his life and all nice names. Its better for me he is gone as he can be very aggressive (verbally), and was scared that could turn into physical, he uses xtc, marijuana, poppers, ghb on regular basis and i suspect he uses other things too. He is too confusing as he can be too nice and make me feel like a princess and later turn into a monster out of the blue.
My problem now is i have severe heart beats,cant eat and am shaking. Am not on drugs but how can i deal with this pain. i feel like my heart will explode. Help!
Thank you "Jo" and "Femme Natale" for the answers. I hope more people will answer as this makes me very strong.

The pain is i feel i have lost a dream, i started this relationship thinking it would last. I tried getting him off drugs but he insisted he wasn't using much of it and i let him enjoy those without me. I pushed him into therapy coz he too came out of avery abusive family (to the extent that one of his brothers died and they decided not to tell his mum) but he stopped therapy after 2 sessions. As regards diseases, i had him tested for HIV the day i fell in love with him, when i found out he was contacting his ex too often, protected sex took over which angered him a lot.
How did i get here, he is extremely manipulative and cried a lot every time i told him i was leaving him if he don't drop the ex.
Once my panic attacks are gone i will not let him anywhere near me but i feel so deceived and disappointed. Hope my story will inspire one in a similar relationship to dump him