I have a couple of friends (one a former co-worker, the other a friend thro church) whom I've shared a shower with (naked) after the gym on a few occasions.
Going back a few years, when I bought my first house I had a younger straight lodger (his gran was actually a friend of my mother). One morning I realised he had overslept for work and knocked on his bedroom door and poke my head round to tell him he needed to get moving - he immediately through the duvet back and sat up stark naked - I quickly backed out of the room so as not to embarass him. But then a few weeks later, I came home from work and rushed up to the loo, not realising he had come home early and was in the bath. I backed off quickly and apologised. He said 'no problem; come in an use the loo if you want - I'll pull the shower curtain across'. So I did. As soon as I finished peeing and flushed the loo, he pulled the curtain back and started talking to me quite naturally about our respective days at work. As he was immersed in the water, I couldn't really see very much, but it was clear he was quite relaxed being naked in front of me.
Shortly after that, we decided to decorate his bedroom. and I gave him the option of moving his bed into my study (which was quite poky), or into my large bedroom, while the work was going on, and he chose the latter. As I knew now that we both slept naked and he wasn't too bothered being seen, the first night, he followed quite quickly after me when I went up to, and I made a point of undressing in front of him and taking my time getting into bed. He then proceeded to finish undressing as we chatted, and gave me a very relaxed full frontal view as he got into bed.
We carried on chatting and I mentioned something about him being very relaxed being naked in front of me, and he explained that his parents were both naturist and he had grown up going with them to their caravan on a naturist site, and while it wasn't particularly his thing, he did still spend the odd weekend with them there, and didn't have a problem being naked around other people. So from then on, we made no effort to cover up in front of each other around the house (though we never really sat around naked watching tv or anything) and shortly after both joined a gym where we would shower together and be naked in the sauna, and were quite relaxed about using the bathroom when the other was in the shower or bath. Nothing sexual at all, but just two guys happy to be naked in each others' company.
I was hired to remodel a Dr Office over 2 years ago. I quickly became friends with the Office Manager, female, and since we are both single and I was cruising on Carnival Cruise Line solo, I invited her to join me on a cruise. She was hesitant at first, but when I explained it would only cost port fees and taxes for the 2nd person, and the beds could be 2 twins or 1 king so she didn't have to worry about sharing a bed, she quickly agreed. She fell in love with cruising and has been on probably 10-15 with me since. We also travel together quite often to land based destinations. We have became great friends, and I am always naked whenever we are in a cruise cabin or in whatever accommodations we have at our other destinations. I have seen her naked a few times, but only because I have been in the room whenever she has had a shower, or she's getting dressed for an occasion. She doesn't hide or shy away like she used to, but she also doesn't remain naked like I do. She definitely doesn't complain about me being naked. She even joined me on Haulover Beach in Miami last year when we had an entire day waiting for our flight after a cruise. She remained dressed while I was completely nude. We even walked the beach quite a while, and of course we encountered several nude people. She definitely doesn't have any issues with my lifestyle nor being around other nudists, but she's not comfortable being nude around others. We remain great friends and will hopefully be lifetime companions because she is a great person and we really have a great time. I am so grateful there is no pressure for the relationship to be anything more. I truly love her but not in a romantic way. I have 2 ex wives and neither of those relationships were ever as good as our relationship, and I definitely don't want to ruin a good friendship with sex or anything else that might cause stress between us.