Please help am in deep trouble

I am hindu boy. I have been in relationship with a christian girl for the past 1 year. Our relationship has been quiet a roller coaster ride. We have had numerous fights. Each time we fight we get back somehow then we fight again and this cycle repeats. Recently we had a fight on religion. She asked me to convert to christianity for marriage. I was not ready for it. We had a bitter fight. She said all sorts of rude things to me. I just couldn't bear it and i broke up with her. Now she wants to get back. This has happened always. I have got tired of it. I am quiet sure that we wont have successful married life.

BUT am feeling guilty that we had sexual relationship. We had sex many times. She feels like I have dumped her after all physical relationship got over. But its certainly not that way. I felt we dint have future and thats why I took the decision to end our relationship. Now am feeling guilty. What should i do. In the past we had been through break ups. We got back and we returned to the same position in no time. Please tell me what i should do. Did i do the right thing or was i wrong.