Your English isn't the best, so it is a bit difficult to understand you.
How long have you two been dating? How old are you two?
I will agree with your gf; this is a waste of time. You two want two different things. She is looking for someone who is interested in marriage and you aren't. I don't think you both made your intentions clear PRIOR to having sex.
I would recommend you move along and not waste your time or her time.