What is the most romantic way to ask for a prenup?

Sign your name across my heart....and also on the bottom of this document please

I care about you so much that I don't want our eventual breakup to cause any unnecessary acrimony between us.

I´ll sign yours , if you sign mine.

leave a trail of rose petals and candles leading to the document

sidenote: make sure the candles are of the fake, non-burning variety

If you don't trust her ,you shouldn't be marrying her

post a note on your hard on and present it to he like so.

Mid blowjob