I like for my woman to dress up and look good, maybe even just a little sexy when going out in public. Makes me proud to have such a lady on my arm, and if some dudes eye her just a bit, all the better. In fact, I would tolerate and enjoy her looking more sexy when going out WITH me as opposed to going out WITHOUT me. BUT and this is a big BUT. There is a limit to that. If she is showing too much cleavage or too much thigh or her clothes just hug her a bit too tightly, that is not OK. Where do you draw the line? That's very subjective, and each couple and even situation is different. I think the lady should be very aware of her man's feelings and the man should be very open and honest. He should speak up in a respectful manner, not confrontational, that "honey, that blouse just looks a little too see-through and that makes me a bit uncomfortable. Would you mind changing?" The lady should absolutely respect his feelings and change into something more modest. In fact, if there is any doubt at all, the lady should ask her man what he thinks. There is also a bit of a burden on the man to allow his lady a certain amount of flexibility to express her own personality and yes,her own sexuality. After all, that's what separates the genders and makes us attractive to each other.
It all comes down to trust and honesty.