I would say that it’s better if you let this rishta go. InshaAllah you’ll find someone better. You say that the hatred is building inside you…which means that it’s growing instead of subsiding. And to build a marriage with someone on a foundation of hatred…is very risky. Even if the guy is “innocent”, what guarantee is there that you won’t transfer your hatred for his family over to HIM from time to time? And what if this guy is the kind who doesn’t feel comfortable getting involved in future arguments between you and his parents? What if he’s the kind to blindly support his parents all the time? Then what? Wouldn’t that make matters worse for you?
****Also, if this family has both deceived and betrayed you…then WHY ON EARTH are they sending a rishta to you? Have you wondered about that because I find that strange. If they betrayed you…that means they didn’t care enough about you and your family to begin with. If they didn’t or don’t care about you…then why send a rishta? Or are they sending a rishta because they feel bad and want to make amends for their mistakes??? If that’s their intention…then you have to decide if you should agree to a proposal as a peace offering. If it’s forgiveness that they want…then you can choose to forgive them without becoming a future member of their family. If you’re not “in love” with this guy (no matter how innocent/sharif he is) then inshaAllah you’ll find a guy you feel more strongly for.
****Also, don’t marry into this family to exact revenge either. People sometimes get what’s coming without us having to try too hard.