Reb Golem Gorilla (is that what G&G stands for?),
Your added comment that he is a yid and an ‘affiliated’ (perhaps heavily so) yid is a major difference.
Though I have not personally dealt with one in a business setting, they are unfortunately notoriously the hardest because you stand as a representative against who they are (or so they think).
Another important distinction is how long has he been your boss. Did you move into a higher position and now have him as your boss – or switched companies – or this is a long standing problem.
My suggestion (if it is relatively new relationship or gig) is stick to your Torah guns. Find reasonable, healthy parameters for your frumkeit vis-a-vis what food you eat (and how you attain said food), how to fit in mincha into your schedule, how many hours before Shabbos to leave, your Chol HaMoed/Purim/Fast Days schedule etc. Figure out what you are comfortable with (probably good to include your Rav and wife in the brainstorming), and just do it. Keep at it, do your thing, and of course do a great job at your job. Of course, that is easier said then done – but if you have come to the conclusion that you are reasonable (and you are), and you are who you are (and they technically can’t stop you) – then that’s that. Over time, I assume that the tensions will mellow, and perhaps a mutual respect can develop. Reb GG does this, I don’t like it, but what I am supposed to do about it.
Another thing is be aware of your boss’s life. There could be a time that comes up where you can slip in a nice thought or what have you – and it could melt the ice very quickly. In addition things likea fresh box hamentaschen on (or around) Purim, Happy New Years cards on Rosh HaShana etc. might be taken the wrong way, but if done without any sense of frummyness also might over time be a good way to connect.
Hatzlacha,
DQB