Re: Age gap marriages.
There are many reasons why a marriage will or won't last. I don't really think age difference has any more influence over whether a marriage will or won't succeed than anything else.
Getting a divorce is much easier now than when I wore a younger man's clothes, so irreconcilable differences or unreasonable behaviour nowadays is more likely to result in divorce than it did back then.
When I married my Lovely Cousin she was a teenager and I was nearly thirty, but nobody that knew us thought it was odd, or thought it wouldn't last.
We are now approaching our thirty eighth wedding anniversary this year, having known each other for forty seven years. I think getting to know each other properly first was a major factor in our success.
I think for a partnership to last, people must like and respect each other just as much as they love each other.