Why is it wrong? You're not cheating. It's just fantasy. I haven't stopped noticing other women who I think are really attractive either. I just don't try to fuck them. Doesn't mean I can't imagine what it might be like.
Coincidentally, tomorrow will be our 23rd anniversary. You don't stay married 23 years and never fantasize about what it might be like if your life had been different and you had been with a different woman.