I started underdressing over thirty years ago when I was dressing for work and was out of clean (men's) underwear. I mentioned this to my wife and she said (kind of jokingly) "well, wear a pair of mine." So, I did. I found that they fit perfectly, were far more comfortable, and gave me a little rush. I have been wearing panties ever since. My wife and I share panties - we have only one underwear drawer for the both of us. I have been wearing them so long, I don't care who knows. I don't own a pair of men's underwear, and haven't for many, many years. I wear them to the doctor's office - I have a female doctor who is also a friend, and she actually encourages me to wear something "interesting" when I come in for a checkup. I pick the frilliest pair I can find - silk, lace and bows - pink or flower pattern - sometime a thong - when I go in for an appointment.
Most of my close friends know I wear panties, and sometimes when a couple comes to the house to watch a game or something, I'll hang around with just a pair of panties on. Recently, I went on a guided whitewater rafting trip and had to change into a wetsuit in a locker room with about thirty other guys changing. I was wearing a pair of black, sheer, nylon/spandex bikini panties with tuxedo lace. Nobody even raised an eyebrow, and I wouldn't have cared if they did. I'm very comfortable with this.
I wear pantyhose in the winter, and babydoll nighties to bed, but that is the extent of my crossdressing. I would love to CD full-time, but it just wouldn't look good - I'm just not built right. I have no qualms at all about going ito a store and buying panties or nighties.