Take it from a "homo": You don't know anything about your future wife! Get a fucking clue.
A quick lesson on this kind of woman for you.
1) She wants it, therefore in her mind, SHE NEEDS IT AND DESERVES IT. Her mind is already set, she's working on changing your mind. Any disagreement means she just has to work harder.
2) She wont stop talking about it until she gets it.
3) She will manipulate you in any way to get it. She wont settle.
4) The more you tell her no, the less she'll think you love her, or so she'll say.
5) Most of them go for what people can see first, this one's working in reverse, she will be VERY expensive long term and her excuse will be "Everyone can see *fill in the blank*, this is important".
6) After it's done she'll turn around getting the pussy work done as being mainly for you, not her.
Now that said, one more piece of advice that you'll thank me for later.
DON'T DO IT UNTIL AFTER YOU'RE MARRIED
Good luck with that!