is this wrong

so i’m like fwb with this guys. FYI hes told me he’s wants to date me multiple times and i told him i’m not looking to be in a relationship rn. So i guess that shows him i’m not only talking to him at the moment and that i only wanna just keep having fun but, the thing is im also talking to one of his friends. so my question is... would fucking his friend be kind of rude and like complicate things or do u think he wouldn’t care.