It was probably a marriage of convenience, he wanted another child, and she wanted to be kept well. Many in that bracket want to have a certain status.
Unfortunately for Melania she got a piece of shit, Trump was caught having affairs while she was pregnant, and he probably did pay to get back in her good graces. But Trump got a son out of it, for him, that was a good trade off. It is not like trump actually gives a shit about her, or anyone else.
Now as the years have passed, trump went back to being the low life he always was, and Melania tried to keep some kind of dignity, but she was trashed so many times by trumps many sexual affairs.
She probably did negotiate a great financial deal when he became president, it is probably one of the reasons it took so long for her to come to the white house.
She has learned to stay with the low life trump, but it was a trade off, it was always an arrangement based on financial security for her, and for him some kind of women to be seen with.
She is a very hard looking women to look at, probably many cosmetic surgeries, and just living with trump. It has to take a toll, it took a toll on America, but luckily, we tossed trump out of office quite easily.