Theresa had confessed her love to Ethan just before Gwen arrived. That's when she found Ethan and Theresa in a compromising position.
Gwen finished up her business trip and returned to Harmony the next day. Ethan started to feel something for Theresa and called Gwen to come home as soon as possible. Theresa made the most of the time and tried to get as close to Ethan as possible. Gwen went out of town for business and suggested that Theresa assist with making the wedding plans. Ethan still ended up proposing to Gwen despite all of Theresa's tricks to make him fall in love with her instead. He forgave her for the stalking and the two of them started to get close. It was later discovered that his stalker was Theresa Lopez-Fitzgerald. When Gwen turned him down because she didn't feel that his whole heart was in it, someone began stalking him.
A reluctant Ethan was pressured into making a commitment to Gwen by his aunt Sheridan. After graduating law school, he returned home to Harmony and began working for Crane Industries. Ethan grew up with Gwen Hotchkiss and the two were always believed to be meant for each other. Julian still remained is his legal father and was listed on his birth certificate. The oldest son to Ivy Winthrop Crane and Sam Bennett, Ethan Winthrop found out that Sam was his biological father, a man he hated, at his and Theresa's engagement party.