Is it normal to want to tell my feelings to her?

i m having a very good friendship with a woman for last 1 yr, but now i think i m getting attracted twds har and want to have sex with her... she is also very open and we are comfortable in sharing any topic. Problem is i m married and she also is married .. and nowadays i m getting very attracted twds her and wanna have a sex eith her .. but don't know i to proceed