Are jokes about hot young women marrying rich old men ever funny?
No, they're not. But they are ubiquitous. This is because we, as a society, recognize that there's something wrong about these sorts of relationships, but nothing so wrong that we can't laugh at them. More or less, they reveal in their participants what society has judged to be an unhealthy overvaluation of either sex or money and an unhealthy devaluation of romantic love. Note that both of these cartoons make clear that this is an either/or situation. These women have chosen money over love. They are bad.
But nothing is ever the case of merely pointing and laughing at the supposedly immoral freaks. Rather, we recognize in these relationships our own unhealthy overvaluations of sex and money, as well as the instability of romantic love. What do we do when, as so often happens, a woman in one of these relationships claims that, no, she really does love the withering old fart she has married? Well, we do as the authors of these comics do: we assume they're lying. Hence, "My biggest fear is that I'm going to slip up and say what I'm really thinking." What they're really thinking. Except, of course, what if what they're really thinking is that, no, they actually do love this fellow? It's unthinkable, so our jokes don't allow for the possibility.
But the whole reason the jokes exist in the first place is because of that very possibility. We know that what must have drawn these people together in the first place was her sex appeal and his money. Given that, if they actually do love each other, it could mean that that's all love is. In which case, romantic love would lose its mystical quality and be reduced to nothing more than a set of external circumstances. Which would make our own relationships not so different from those ones. Because, after all, weren't we first drawn to the people we've been with because of their sex appeal or their signs of financial success or some other similarly cold, hard material marker?*
On the other hand, isn't the transcending of all boundaries supposed to be part of the mystique of romantic love? So why do we assume that age is the boundary that can't be transcended? That if you're with a person twice or half your age, you must be with them for precisely the same reason that first attracted you to them? Because, after all, that's the part that's immoral, right? The failure to move from the initial material attraction into the mystical realm of romantic love?
This becomes all the odder when you stop to consider what is perhaps the dominant trope of the comics section, at least among the most hackish strips: "Ha ha, doesn't marriage suck!" Examples of the form can be found here, here, here, here, here, here, here, here, here, and here.** But Hagar the Horrible is the comic that works best for our purposes, as it often plays off the harsh transition from romantic love to marriage.
Here we see Helga schooling her daughter, who is often depicted as being head-over-heels in love with her lute-playing boyfriend, in married life. The basic lesson seems to be that it's utterly miserable, except for those times when you can get away from your husband. Likewise, the only times Hagar's ever happy are when he's away from his wife, usually off drinking or raping and pillaging. And then we get jokes like this:
And we see nothing wrong with them, even though they feature characters expressing the same sort of materialistic valuation that was castigated in the cartoons above. Here, somehow, it's not an overvaluation at all, but merely a perfectly reasonable desire, a way of saying, "I'd like someone sexier and richer, but romantic love stuck me with you." We're not immoral bad like the hot young things or the pervy old coots above, because ultimately we chose romantic love, but it did lead us into a bad, albeit moral, situation.
And so what are these comics telling us? They're telling us that romantic love is morally good, but also a transient and naive hope. Further, despite being good, it stems from base materialistic desires and leads to a lifetime of misery. In other words, it's an ephemerally good thing that comes from and leads to materially bad things. But because the materially bad things it comes from are considered immoral, we do our best to not acknowledge them, whereas we often talk and joke about the materially bad thing it leads to, because it is considered moral. The jokes about hot women and old men exist to reinforce the myth*** of marriage based on romantic love, while the "Ha ha, marriage sucks!" jokes exist because we feel suffocated by that myth.
It seems to me that we're rather conflicted about all of this.
*Not that we willingly admit this. No, we married the person we married because they were The One, right from the very beginning.
**Of course, not all comics depict marriage as a barren hellscape. But the trope is widely used enough--and not just in the comics section--that I think it's fair to say that it represents a widespread cultural anxiety about marriage, which for the last couple hundred years or so has been based almost exclusively on romantic love, which, as these comics show, we have a whole other set of anxieties about.
***I use "myth" here not as a pejorative (as in, "It's just a myth that dolphins are gay sharks"), but rather as a synonym for "cultural story."