Once he started with his prime time show he dumped her

Old School Soaps
Back in the day when Luke and Laura were just being introduced to the world, this cast member on the show had a great two year run.

Everyone thought she would stick around forever.

She was having a relationship with another actor on the show who would move on to the big time of prime time.

He was supposed to take her with him so she quit.

Once he started with his prime time show though he dumped her and she burned so many bridges leaving GH she could never go back.

Richard Dean Anderson
Susan Pratt

Source: http://www.crazydaysandnights.net