Run as fast as your leg can carry you.  This is why premarital sex is not good.  If we "hit it off" quickly having sex and all that only to discover that we are not compatible with the person, the main losers are the women.  You cannot help this guy and he cannot help you either.  You seem to be a person who would love have an honorable family life experience.  Look elsewhere.

We all make mistakes.  But the pain you are going through is evidence that premarital sex is evil and bad for everyone.  Regardless of how many people are involved in it, it is still bad and evil.  We would have peace in our lives if we decide and succeed in avoiding it.  It was good you broke with this man.  The truth is that even if you people should marry, there would be no trust in that relationship.

Do not kill yourself though.  Go and repent of their sins.  Also ensure that you stay away from sex until you are married.  The only people who can succeed in pretending to be having fun with premarital sex are those who are doing it for money - whether a full time prostitute or the executive ones.

Confess to your Bishop or whoever is your spiritual leader and follow his counsel and you would be whole again.

Good luck.

Francis