Separate houses is the key to George Clooney and Stacy Keibler's happy relationship.

The couple have been dating for almost two years and friends believe their romance has lasted this long because they don't live together.

A source said: ''She still has her own place in LA. She thinks it's best not to give it up completely and George agrees. She never goes there. She practically lives at George's - that's definitely a sign he's committing 100 per cent to her.''

Although Stacy, 32, doesn't officially live with the 52-year-old actor, George has made changes to his pad to make the ex-WWE wrestler feel comfortable.

The source added to Life and Style magazine: ''He had a mega closet built for her. She's such a big part of his life now that he's customising his home to fit their needs as a couple. It's very sweet!''

It was recently reported that one of the things the Hollywood heartthrob likes most about Stacy is her independence because too many of his ex-lovers suffocated him.

An insider previously said: ''She goes off and does her own thing whenever George is spending time with his pals or is deep into a film project - she doesn't even call him. But eventually, he starts missing her and he's the one who calls. She lets George come to her.''