marriage prayer

I'm 23 yrs old.I'm the second daughter for my parents.My parents suffered a lot to make us both settled in studies.Now my sister had a small 2 yrs baby.she did a love marriage without my parents satisfication they missed their happiness because of her love marriage and now i got an aliance from a very good family.i really love them all.but my fiancy was not talking with me for above 3 months our engagement also fixed by august month.but what he has planned i dont know.In this i made a very big sin that i loved a guy in my college days,later after my sisters problem i spoked with him directly and I moved from that relationship its upto 2 yrs gone he didnt disturbed me for any kind of reasons.I thought of discussing about this with my fiancy but I'm so scared on him because he is not a such a kind of person to accpet those all.now I dont need a relationship rather then my fiancy. I need a life with him.I need to ask sorry to my lord for my all sins.As a girl i cant survive in this world alone please pray for my marriage life that my fiancy want to accept me as his wife without any doubts.I want to live my lord gods gift life so happily and peacefully i missed my sleep for a long days SO Feared abou my future.I wont sin abck again.god only gave this realtionship for me and now its trying to get away from me means how i can tolerate that.so what i beeging my god for his mercy.