United Kingdom, April 24 -- Jay Leno thinks his marriage is "defined" by how he cares for his wife following her dementia diagnosis.

The 74-year-old actor has been married to Mavis Leno, 78, since 1980 and while she has always been a "very independent woman", he has had to step up and take care of her since she was diagnosed with the condition that affects memory but insisted that he likes being "needed" in such a way.

Speaking on the 'In Depth with Graham Bensinger' podcast, he said: "When you get married, you sort of take a vow: 'Will I live up to this? Or will I be like a sleazy guy if something happens to my wife, I'm out banging the cashier at the mini mart?' No, , I didn't. I enjoy the time with my wife. I go home, I cook dinner f...