I cant stop fucking my friends' girls

So for a few months now, Ive been having affairs with 2 of my friend's girls. The girls are unaware that Im fucking them both, well they dont really know each other that well so im not really worried about that. But I feel so guilty about it. It all started when friend 1 cheated on his girl, then the girl basically came up to me because we knew each other from time and it just happened, ever since then shes been doing it with me, and says stuff like, I love Jerome but I like having sex with you, and girl 2, well i think shes just a hoe so its fine, but she is dating my best friend so Im going to tell him. My question is, is it normal for me to be having these kinds of relationship with them because I feel like not telling my friends about me having sex with their girls and just keep in it going. Or should I just tell them and suffer with whatever happens