This is actually why I hesitate to get involved with someone because a lot of couples seem to stop being attracted to each other after a while.
It's evolutionary. Over time, most women generally become less and less attracted to their partner (there are actually studies on this) It does make sense, of course - where's the evolutionary advantage to having 6 kids with the same guy? There isn't one. Biologically, as a species, we are just not really wired for lifelong monogamy
It's actually pretty upsetting, to love someone and want to want them, but your body is like "meh, whatever". Generally with men, although after time they want some variety, they do still retain a decent amount of desire for their partner.
I guess the solution is to accept the reality and not base what you plan to be a long-term partnership on sex. A lot of people could stand to more pragmatic about this. Marriage is a compromise - and normally if you want the stability, the emotional support, the kids, the shared income, the partnership etc then you have to sacrifice the fireworks. People tend to want to have their cake and eat it in this regard when in reality, it really doesn't work that way. If and 'exciting' sex life is more important to a person than companionship and a family, then stay single. If you want a family, then accept the compromises that you have to make. Different people are going to have different priorities in this regard.
Would that be really a downside if he's rich?
I've dated rich guys and I find it can set up the kind of power imbalance I really don't get on with. I'd rather make and spend my own money than spend someone elses. But I'm the kind of person who really cannot stand being told what to do by anyone