Nick and Vanessa Lachey's marriage hasn't been a ''walk in the park.''

The 44-year-old actor has been married to the beauty queen for seven years now and, although their relationship has been challenging at times, he doesn't think they'll ever break up because they're committed to working through their issues.

Speaking to 'Entertainment Tonight', Nick said: ''I think if people make it to seven years of marriage, that's long these days! Any marriage is challenging -- it's certainly not a walk in the park, but we're very committed to each other and to working through those challenges and I'm very confident there's nothing we can't get past.

''I don't know if there's any truth in the seven-year itch. We've always found a way to keep it interesting. We've been together 12 years, have a beautiful family and are very blessed, and there's just never a dull moment around this house.''

The couple have three children - Camden, five, Brooklyn, three, and Phoenix, 18 months - together but they're determined to keep things exciting in their love life even though a lot of their time is taken up by their kids and every day household tasks.

Vanessa, 37, explained: ''Every night I cook and he cleans up -- that's our deal! We talk about the day and funny things with the kids, pour a glass of wine, then sit down and watch something. We love Netflix!

''It still feels like I have my husband, instead of like we're going through the day mechanically with breakfast, lunch, dinner. It can get that way with three kids. You wake up, get shot out of a cannon, then it's go, go, go until they go to bed!''

And, although they're very happy with the three children they've got, the brunette beauty hasn't ruled out adding anymore little ones to her brood in the future.

She said: ''Nick thought we were done with two -- I think we both did! But Phoenix has been the best surprise. He's like the missing piece of the puzzle that we didn't think we were missing until he came into our lives and now we feel more complete. There's definitely no plans as we're loving having the three, but you never know.''