Here's a list of duo templates I know off the top of my head:
https://toyhou.se/2382249.duo-6- (Gumroad to buy this is here: https://gumroad.com/bakusatsu?sort=page_layout#jeYSa)
https://toyhou.se/6060534.-profile-double-trouble
https://toyhou.se/3524828.-f2u-lovestruck and css version: https://toyhou.se/3586476.-8-800p-frames-css
https://toyhou.se/6841103.-3-relationship-cards
https://toyhou.se/7028957.extensive-ish-relationship
I hope you're able to find one you like!