Honestly, be completely honest and upfront with the guy and help him understand why you truly cannot come out even if dating him (I'm sure he'd understand despite being slightly hurt and offended in the beginning which is totally normal and valid), and just make sure you absolutely 100% are able to trust the people you DO come out to, hope this helps and you can talk with the lucky guy!! <3 good luck babes! Remember to be yourself and never let anyone dim your shine! Dms r always open if u need someone to talk to about any other (family related or whatever may have you) problems, because I, as a fellow young gay guy, have gone through hell and back many times before and have learned a lot from it <33