Is it okay to look for a serious relationship while having a fwb?

I have a fwb and I have feelings for him. However he wants nothing more of me. I met a new guy and he is interested in me. I think he would be a potential long-term relationship. Is it okay to get to know this potential good guy better while I'm still with my fwb? If things don't work out with the good guy ( I dont know him well) I don't wanna lose my friend either..