One can exercise this muscle without urinating. After you've exercised it for at least three weeks and built up some stamina, then you can better control ejaculation by squeezing that muscle when you feel the climax approaching. With a lot of practice, a man can literally experience the same full body orgasm as a woman without ejaculation. Some men practice this and they don't ejaculate for days, for weeks, and others don't ejaculate for months. Yes, sex during menstruation is perfectly okay.
Some women complain that they are more sensitive and some men are turned off for obvious reasons.
Physiologically it's absolutely okay. I believe it should be a ritual at least twice a day for twelve seconds in the morning and twelve seconds at night. You can also touch each other, caress, you can whisper erotic fantasies in each other's ears and you can build sexual anticipation for later on when you have more privacy. I think one way to maintain spice in your love life is to flirt with your lover in public, because flirting instills confidence and makes people feel good. I think holding hands and kissing and even having code words is a lot of fun and just communicating erotically.