You break up with him:
"Stefan I love you more than anything in this world, you're my everything and I know you'd disagree but I think us breaking up will be best for everyone at Mystic Falls" I cried wiping my eyes as Stefan stood letting himself go.
"I can't let you go Y/N, you promised me a forever and I did too.. I can't lose you Y/N, I'm losing everyone that's ever meant so much to me" he was fully crying now. "I love you Y/N"
"I love you too Stefan but I have to do this.. Goodbye"