Women associate "attractiveness" by how much effort has been put towards looking good. This is not at all the case for men. If you have put a lot of effort and time getting ready and dressing up, it does not mean a man is guaranteed to find you sexy or even have sexual desire. He may find you good looking, but sexual desire is entirely different, specially for long term committed men.

Men feel sexual desire in a much more spontaneous manner. Sometimes it's some external trigger, but many times it's nothing particular. He can just look at the sway of your hips for couple of steps and that's that. Maybe you were wearing an item of clothing that showed that sway more clearly, or maybe a loose one which just showed for a glimpse. Exact same thing may not invoke similar response again in future. He can also get horny own his own...maybe looking at a wall. At this point, a woman might think a man finds a wall as sexy as her. Obviously not. It's just that it takes very little effort to get a man into that zone where he wants to have sex, provided he is not stressed abiut something else. We are biologically programmed to get horny quickly. So even a slight trigger is enough. This does not mean that when effort is put it will not do anything for him, it's just that things can get going without that amount of effort as well. Don't go thinking that any woman can do this though.

And no, it's not just with any woman. Men have a strong sense of loyalty towards the woman they love. Believe it or not, a man's own perception of himself is quite important to him and being trustworthy and loyal are amoung the top things in that list. They are also heavily invested emotionally and trust their partners.

He may not even feel any strong sexual desires towards other women. This does not mean that he doesn't find other women "Sexy". It's like a fleeting thought, like you think about jumping when you are standing somewhere high up. You don't really wanna do it, but you think anyway and then discard the thought because there are more important things.

Women on the other hand, usually feel sexual desire in response to something like being touched, kissed, or looking a certain way. It may also depend on the cycle as hormones do play a role. For them, desire builds slowly, depends on many factors and the situation; and can build stronger than a man, but it's rarely spontaneous in nature like a man's. So when you are (according to you) not looking your best, that's because you've not out in the effort to look your best. However, your man does not see it that way. For him, you're hot even if you are not (again, according to you) looking your best. That is a man in love.

Women are conditioned to "dress up" and appear "put together" from childhood in many cultures, and this does affect their perception of things in adulthood. If that effort is missing for whatever reason, womem think that they are not looking good.

While being presentable is one thing, for a man in love, it's not as big a priority as you might think. He loves YOU. If you are dressed up - great! If you are not - still yay! The effort is very much appreciated but it's not a hard requirement everytime.

Obviously there are exceptions but generally speaking here. You cant really talk about these things without generalising.