Maybe you could use the old saying that money cannot buy happiness. The protagonist is rich, spends his money on things he doesn't need, fast cars....um, carriages, and loose women. But, one day he sees a couple who are happy together. Realises he is not so happy himself and decides he wants a piece of that pie himself. Well, to start with, he does things how he has always done them and tries to use his money to get what he wants. But of course, his efforts are promptly rebuffed.
Oh I know, it's not the most original of ideas. But thats's where you great minds all come in to put a 'twist' on it.