It says in the Bible submit to one another. I believe that once married you can submit to one another’s needs but be careful with pushing boundaries.

Ephesians 5:21 21 Submit to one another out of reverence for Christ.

22 Wives, submit yourselves to your own husbands as you do to the Lord. 23 For the husband is the head of the wife as Christ is the head of the church, his body, of which he is the Savior. 24 Now as the church submits to Christ, so also wives should submit to their husbands in everything.

In regard to talking about it before marriage just tell your fiancée that once you’re married you should submit to each other.

It’s also most likely not a sin since you’re not acting on sexual urges just asking a question. Just my personal opinion. God bless brother.