Just to respond to some people's comments, I think BizzyBee hit the nail on the head about what I wanted to know:
Quite simply, aside from other consideratios, Jehovah's Witnesses must choose from a very small pool, which leads to odd couplings age-wise. This is further exacerbated by the fact that JW's think Armageddon is around the corner and that marriage is not necessarily til old age and natural death.
Of course I agree that people of varying ages can actually love each other and not marry just because of considerations of other types. I have absolutely no problem with marriages in which the man is younger than the woman. That happens "in the world", and, where I live, some particular circumstances have made it much more common than people like to think. I wanted to know whether the fact that you have to marry "only in the Lord" was taken to mean that man (whatever his age) marries woman (whatever her age), and not simply that OLDER MAN (whatever his age) marries (very young) WOMAN. If this principle is taken to mean "Man, you get to marry chicks", then it is perverted. Some of you don't know this, but I'm a worldly and I need to ask questions that might seem stupid (sometimes they are), but I lack the basic knowledge you guys can take for granted.
I believe that the old man who remained single until, say, his forties, and marries a young girl in the congregation, say, in her early twenties, is not simply finding young flesh. He is to marry and he follows the idea that younger flesh is best (which is not the case). I would believe the same about the older woman who enjoyed "the gift of singleness" and married a younger brother. And then, from what I read, second wives or husbands are quite often due to the fact that the witnesses were not allowed to really get to know each other well.
I'm aware that there can be other reasons for such marriages. Suppose Sister Very Hot marries Elder Very Old but Theocratic. Maybe they love each other, maybe he is marrying for the young flesh, maybe she is marrying for the perks... you get the picture. I wanted to sort of explore the dynamics of love and marriage within the WT. I believe that a lot of misery and problems arise from the requirement that you "marry only in the Lord". I believe that the sisters who marry out are perhaps doing the smart choice.
By the way, this question of mine doesn't come out of thin air. I happen to have met a man, in his seventies, who was made an offer that he was supposed not to be able to refuse. This man made some good money and his wife divorced him at 69. The wife was a closet lesbian who thought she didn't have to hide her real sexuality now that she was old, and moved out with someone else. The man was shocked and tried to find "a spiritual answer", so he was approached by some witnesses, who managed to make him attend meetings, study with them, et cetera. He refused to go door to door, and that was why he got stuck in limbo. One of the elders in the congregation pointed out that Sister In Her Forties still looked good, but, er, she could marry only in the Lord. The man was a lifetime friend of ours and told us the story. He thought he was being offered a woman in exchange for baptism.