Think I've got a bit of a thing for the executive director in my company, what should I do?

I have been in this assistant job for about 1 year and he is this new executive director(for 3 months). He is 12 years older than I am, besides, he has a gf, who he has been with for about 7 years. I see him every single day, there is no way I can avoid him or keep distance. What should I do? How could I suppress my feelings toward him?