Chemistry

I’m looking for recommendations for books that have insane chemistry between two characters, and not just sex for the sake of it. Not looking for chick-lit. Something with a bit of depth.

I’d prefer M/F, but open to M/M and F/F also. Can be historical or contemporary fiction.

For context; I loved “The Safekeep” and “The Bronze Horseman”. Both had huge build ups.

Thanks!