There are lots of married women who many of us single (and married men) find attractive. That's "the breaks." Deal with it. Don't go fucking up a person's marriage. Not only does it show disrespect for the woman, but it's a real assault on the husband, and a tremendous danger to their kids.
Keep your dick in your pants and find yourself someone who is available. Based on your writing style and grammar, as well as spelling, I suspect we're dealing with the scenario of a much older woman and a very young man (no offense....or maybe your native language is not English...I cannot tell). She'd eat you up if you got into some sort of a tryst with her, and you'd be left in the dust...
Move on... Forget about fucking her and establish a platonic friendship with her.
My :2 cents: