Mode of Dress For Husband and Wife

Blunt and straightforward: but I need clear answers
Do husband and wife have to be covered when undressed? Besides for in the pool or in bathroom, where I know it’s allowed… When you’re just in the mood of loving… Do you always have to remain under covers if you’re undressed??

Your question is a very good one. There is a mitzvah for both men and women to be tzanua – to act modestly. The Sma”k, one of the rishonim, rules that this mitzvah is one of the 613 mitzvos deoraisa. The mitzvah to be modest is best defined as a positive commandment to act with dignity and self respect at all times, and differs per the situation. How to be dignified is subjective, it wouldn’t be undignified for a teenage boy to wear a sweatshirt when it is cold outside, but for a Rabbi of a shul that would be inappropriate.
Each person has to think objectively about themselves, where they are in life, and what is proper for them to do. It is not always easy to act properly, indeed it is difficult to act with proper dignity as befitting one’s stature at all times. One should try to take small steps toward the proper way of acting. It may not be proper to walk around one’s home in boxers and an undershirt, that is undignified, but one may not be ready to take the step of always being dressed when outside the bedroom. The best course of action is to take baby steps. Perhaps trying to always wear shorts, maybe it would be to wear a robe, whatever one is comfortable with that will elevate them towards the end goal of being tzanua.
It is proper for a man or woman to be dressed when out of the bedroom, even when others are not around. If one is not holding there, at least try to take small steps toward that goal.
Wishing you the best of luck
Rabbi Shay Tahan