Caught feelings for the friends with benefits

I’ve always been an emotionally closed off person. And avoided relationships of all kinds. Stayed a Virgin till 21 and lost my virginity to a guy friend on my 21st birthday weekend. Anyways we continue to hook up with each other without having a discussion about our relationship. Like his the only person I’ve been doing anything with since.

Anyways I realize that I’ve caught feelings for him but been in denial until last weekend where I had sex with someone els and felt really shit about it, almost guilty.

. (Like the sex was really really good).

Help I don’t. Now what to do how to proceed. Do I tell Fuck buddy about my feelings?