Are you asking if someone who is poly can be satisfied in a mono relationship? I think it depends on the mono relationship. If you are poly and still free to seek out deep friendships and are able to connect with others even without sex then I think it can work for some people. I don't think it can be switched on and off but you can choose not to be sexual with others.
Everything will be ok in the end. If it's not ok it's not the end.