Most Helpful Guy
Cheating part is totally bad... you should have not done it.. I mean if you are in so insanely in love with him, looking for marriage and all then how could you?
Anyways I m sure you must have got carried away in the heat of the moment. Now if you want him back then try to listen him and do as he says (not the oral sex, I will come to that later). Take him out for dinner or something.. spend most of the time together... some surprise gifts might also do the trick.
As far as Oral sex and blackmailing is concerned... these are not justified at all... I guess you will have to deal the blackmailing part very cautiously and pretend that you are not scared of that shit.
For oral sex... I guess you should talk and explain that you can't do it... and if this also doesn't help then you can make excuse that 'You are not making me high enough.. so I don't feel like doing it' :P
Most Helpful Girl
Take his bargaining chip and power back by just ending it with him. If he shows the chat in public you could just lie about it and say that wasn't you. or just say look weve been together 2 years, what do u think we do when were alone play scrabble? anyway don't let this jerk have that kind of control over you. drop him. he won't ever love you again sorry to say bc once the trust is gone and the respect isn't there the relationship will never be the same again