lesbian kiss

My boyfriend wants to be kissed by a lesbian, please don't get me wrong I respect everyone's sexuality but I'm not okay with him wanting to kiss another woman lesbian or not. He really wants to because I've heard lesbians are great kissers and he wants to try it. I don't want to deny him anything in life I just want him to be happy but this bothers me and I don't know what to do. Should I let him?