It’s 100% normal for human beings in any kind of relationship to fall in love. Doms and Subs do it all the time! Most people in power-exchange kink find that love deepens their dynamic.
It’s also part of the human condition that there’s never a guarantee of being loved back.
The real question would be what sort of agreements you and your partner have. If it was your standard, mercenary “fuckbuddy” (not even FWB) relationship then one of the unbreakable strings attached would be “no strings attached.” If that was your initial agreement with your M/S partner then you need to come clean same as if any other condition had changed significantly.
Actually, either way you need to come clean.
Chances that he’ll confess his love vs. chances he’ll freak out and run are about the same as they’d be if you were both vanilla. But either way it’s better to know than to continue to pine. More fair to him. Way more fair to you.
THAT SAID! I’m a Daddy, not a Dom, and to the best of my knowledge I’ve have virtually no contact with Master/Slave kinksters. So everything I’ve said are true in general but may not apply to normal M/S relationships.