Paying alimony to a grown woman?

Of all things you conclude it's US law that makes no sense. This movie was based on a book set in London, written by an english woman and she wasn't getting alimony, her mother lent her money for the rent. You get money if you have no prenup and married to someone rich and bore them a child or put your life on hold in some way to support them.

because USA love womans.

Because he clearly kept the house.. so she needed to be paid alimony.

The threat of having to make alimony and/or child support payments are big reasons why guys aren't getting married anymore.

I have a brain and good taste, so no, I'm not part of the target demographic.

That's what alimony is.

Child support goes to children, alimony goes to ex-spouses.

Who would you expect alimony to be paid to? A young girl? How are US laws the "strange" in this conversation?

We don't have child brides in the US anymore, so of course you pay alimony to grown women.

The main reason most women get married is for the money, the babies, the security, etc. So, when the divorce inevitably happens, it's time to cash in.