Stefan originally returned to town to get to know Elena after saving her from a car accident. They instantly fell in love and began a romantic relationship in season 1, which became strained when Damon fell in love with Elena and Katherine returned to win Stefan back. Though they continuously reassured each other and remained loyal throughout seasons 1 and 2. They fell out of contact at the end of season 2, when Stefan left to save his brothers life. Though they stayed faithful to each other, whilst Elena searched for him, until Damon kissed Elena. She admitted this to Stefan and at the end of season 3 rejected Damon, choosing to be with Stefan. Their relationship was rekindled and lasted into the beginning of season 4. Though they eventually broke up when Elena began to reciprocate Damon's love, and chose to be honest with Stefan about her feelings and intentions. He was determined to move on, before he came upon the discovery that Elena was sired to Damon. He stayed to help Elena in their search to cure her vampirism, throughout the sire bond. He admitted to still being in love with her, and even attempted to seduce her into finding her humanity again. But when the sire bond was broken and Elena chose Damon all the same, it became apparent that her affections for him were real, and Stefan was finally convinced to leave town.