It this relationship really wrong?

I know this guy, he's 59 years old

He met a girl that was 22 years old, she is now 25

They've been together for 3 years

She is slim and beautiful, he could lose a little weight, but he's not fat. Most call him handsome and that he does not look nor act his age. In fact, everyone agrees his heart and mind are at least half his age.

He told me about her and I told him he was nuts.

I then saw them together and except for the age, I thought they were perfect.

It is very easy to see the love between them and everyone who meets them agrees.

She comes from a part of the world where devotion is tradition

He is from the USA.

He is retired and living there and has no intention of moving her to the states. Her says if he does that it will "Americanize her" and destroy their relationship.

They plan on getting married as soon as she is out of medical school.

NOTE:

She is sweet, nice, easy going, and a little crazy, just like him.

So what do you think, is it wrong, or right?