I'll paste in some text from my original post in a similar category to this one, which you may find helpful. For context, I'm 32, U-IC for almost 4 years, and wear Northshore MegaMax diapers to manage it.
The first friend I told was my best friend from growing up- we're lucky we still live in the same city. I had been mulling it over for weeks and finally just texted him saying Hey let's meet for breakfast, I want to chat about something important. I didn't even let myself pause before sending- that way I couldn't back out. He was all concerned though, and when we met up 2 days later, I said something to the effect of: "I've been dealing with a medical issue for a little while now that's been affecting my life and I want you to know." He freaked out and thought I had cancer, so I continued and just said I've slowly been losing bladder control, and the doc doesn't don't really know why yet, so you may notice at some point that I'm wearing a diaper because of it, and I just wanted you to be aware so it wasn't a surprise in case you noticed. He had a couple questions like what work was like with diapers, if anyone had ever seen, if I still worked out, etc. But then actually he got a little pissed at me (sorta playfully) for making him worry for 2 days that it was something more serious. He was like "so you're not dying, you're not moving, and you're not even really actually sick... shit dude I don't give a crap what kind of underwear you have on!" So that was a very positive reaction.
The other situation was far less planned. I have a friend from college that was in town for business- we see each other a couple times a year for vacations and when one of us is in the other's city. It was summer, so it was hot, and I usually only wear a t-shirt and shorts, and of course my diaper. We met up at a brewery (he's super into that scene) and he was late, so before he even got there I felt myself wet my diaper once, so you know, the bulge factor was in play. After a couple drinks he got up to use the restroom, and when he came back, he just said "You uh, might want to pull down the back of your shirt- I don't think you want the whole bar seeing that." I went white and (Idk why) just went "What're you talking about?" as I (of course) yanked my shirt down. He said that because he has 2 young kids he knows what a diaper's waistband look like, and wanted to know why I was wearing one. So I just blurted out the basic explanation. He actually had no idea they made adult diapers like that (I was wearing a MegaMax) but suggested I be more careful about letting it show- he's the "unsolicited advice" friend- we've all got one of those I'm sure.
TLDR for the above two paragraphs: I told two friends, one on purpose because I wanted him to know, and one by accident after he found out by seeing my diaper's waistband, and both were supportive.
Since then, I have also told my step-mom (her and I are closer than me and my actual mom, who doesn't know) as I was over at her house for a family gathering. The evening went on later than I had anticipated and I had some unusually heavy voids, which was filling my MegaMax diaper to its capacity, and I did not want to risk a leak. I also didn't want to leave since I was having a good time, and that also would look suspicious. I mulled over my options, since I didn't think I could explain away taking my bag into the bathroom with me, the noises, and the time. My SM headed to the back of the house, and I got up (did a subtle leak check), grabbed my bag and followed. She's very forward, so as soon as I got to the bathroom she came out of her spare room and was like "How come you're taking your bag into the bathroom?" I said something to the effect of (it's waaaay more articulate in my memory now than it probably was Lol) "Well there's something I've been meaning to tell you for a while and I'm sorry it's tonight with everyone over, but if I want to stay for a bit longer, I need to change my . . . diaper." I briefly explained the incontinence issue, how long I'd been dealing with it, etc. and like any good mom, she was very concerned about my health, and also wondered if there was any other way to manage it. I told her maybe, but wearing diapers was how I was dealing with it now. She ended up telling me to use her own bathroom so it would be less conspicuous, which I appreciated. I changed my diaper and put the used one in my bag to dispose of later. When I came out my SM was still there, and she had more questions: "Have you been to a doctor?" "Have you tried holding it?" etc. I could tell she was annoyed that it had to be this evening that she found out. She also asked "Like, what do you mean, 'diaper'? Like one of those Depend things?" I just pulled one of my other MegaMax diapers out of my bag and showed her- she was surprised that it was a full-on diaper.
Anyway, the evening went on and the next day, we had a long phone conversation about it. She actually apologized for sounding judgy, and just hoped I was ok and that my "secret" was safe with her. She asked if anyone else knew I wore diapers, how work was with them, etc. I jokingly said "Well you didn't notice for the last 3 years, so why would anyone else?"
Bottom line, it helps to tell someone, someone you trust. But you don't have to tell anyone- and likely no one will notice.