I've talked to Caleb about everything, but I don't recall much about Bernard other than asking him about his best friend and stuff. There was never any Fun with Caleb in Bernard's Talk menu, only ever Night with Caleb, which is weird.
Do you have 1 heart with Caleb yet? I can't remember if it's from the fireworks or from giving him a treat (both new options in the Patreon version).
The option to talk to Bernard about you having sex with Caleb is in his talk menu during the day in the shop, not in his home at night.
Admit to Bernard that you've had sex with Caleb, then that night suggest you two spend the night with Caleb, it will start off the same as usual, but then once you 3 bed down for the night the scene will diverge.