Have tried wearing boxer shorts with my jeans and find the bunching-up of the extra fabric makes the experience more uncomfortable. Briefs may work for some, but they are not to my taste.
This ^^ The bunching of boxers is just obnoxious. No underwear for me either. Sometimes when you sit things pinch but I deal
For the occasions when I need support like at the gym I either wear lined shorts or Saxx underwear which has trademarked their products with the "ball glove" which give supports but also isolates the boys from your skin for no chafing. They come in several styles and lengths and material. So when I must I wear some this is my go to choice.
Rough seams do get irritating, something softer is called for. A lighter external layer doesn't work well for durability, so some liner has to be used. But I do not like the bunching issues of long legged boxers, useless extra fabric in unnecessary place anyway, nor the discomfort of snug briefs. So some short legged soft cotton short is what I end up with that's loose fitting. Although it's really relieving when I can work without any of it. After having to wear heavier clothing to keep warm, the relief to get it off is really noticeable. I have seen the lined jeans, but have no use for them. Layering is better, then I can remove the inner layer when it gets warm. Just use sweat pants from walmart for the inner layer when it's cold enough to need more than jeans. Two pairs under the jeans when it really gets cold. But don't like the bulk. Sometimes I put on the insulated overalls when it's really cold, but don't like their bulk or weight either, it's a relief to get them off. Even though my dad was not the least bit nudist, I have come to understand why he moved south, and why he was reluctant to wear long underwear. But he didn't work outside predominately like I do.
I find most jeans a bit rough so I have found some Perry Ellis boxers that are similar to silk but wear much longer than silk. Actually if I'm traveling and in&out of car, I sometimes find my pants slipping due to the soft feel. Cotton anymore holds water to much and feels damp.
I think kilts and togas would be amazing, letting everything breathe, and not wearing anything underneath, but in the US, not sure how that would fly either at work oo at home. A softer seam would be nice, but like someone afore mentioned, it's all what you are use to. I guess your hips, bottom and undercarriage might toughen over time of wearing no underwear.