The actors met on the set of a play in 2009 and are often separated due to busy schedules, reported People magazine.
"It's constant coordinating. It's really hard to be away from the person you love, especially when they're your rock and support system, said Bellisario, 28, back in October.
"It's a challenge but it's kind of perfect because we're such analytic, hyper intelligent people that sometimes just to be in each other's faces all the time might have been too much for us.