"Honeymoon phases end. They just do," said the actor, who has been with Burka since 2004. "I think you have to find new elements that turn you on, and not only sexually."
For Harris those new elements just happen to be his twin kids with Burka Gideon Scott, and Harper Grace, who were born via surrogate in 2010.
"Having kids was one of those great moments for me," he continued. "Watching David become another level of person, mastering this other domain, made me look at him with a whole other set of appreciative eyes. That made me re-fall in love with him."
The How I Met Your Mother star goes on to say that in relationships its important to know that "everyone falls out of love with everything."
"You fall out of love with your house. You fall out of love with your job. You just have to figure out ways to keep [the love] alive," he said.