I honestly would recommend coming at it from a sexual perspective rather than the “couple in love” approach (no offense to the previous commenter.)

I think the highly emotional approach might be overwhelming. It’s easy to have sex and keep it on the down low, but it’s much harder to have a romantic relationship and keep it a secret. With that in mind, I would treat it kinda like you would treat a person who’s curious about their sexuality and not out yet.

Maybe start with something that could be interpreted as a sexual gesture OR an innocent nothing. Could you “accidentally” spill a lot of something on your pants/shoes right before you leave work? When you get home, say you don’t want to get [insert spilled stuff here] all over the carpet/furniture/etc. and casually kick off your shoes and pants at the door.

At that point you’re in your underwear, which will be enticing to him if he’s into you, but not super inappropriate if he’s not. If he sits on your lap while you’re in your underwear, I think that’s a pretty clear signal that he’s sexually interested in you and you can figure out the next step.