The Suburgatory star and the environmental lawyer began dating after he'd become estranged from his second wife, Mary early in 2012.
They were going through a protracted divorce and child custody battle when Mary committed suicide that May, hanging herself in the barn on their New York estate.
Kennedy and Mary had four children. He has two other children from his first marriage.
There are no details yet on when he and Hines plan to tie the knot.