Throughout my life I've pretty much covered the entire "spectrum" on this one, but the bottom like is that I mostly just love wearing diapers--thick cloth, soaking wet, pee-reeking and sometimes loaded diapers--and I like being someone old enough to know better and know that it's "wrong" but I still do it anyway because I love it.
That being said, part of why I love it is because it makes me feel so childish and babyish and throughout my life I've had a fascination with seeing anyone in diapers who is way older than the usual potty-training age but still in them anyway--either because they refuse to give them up or because their parents make them wear them for various reasons.
I really love the "I know I'm too old for this but I'm doing it anyway because I love it" aspect of it. It's very similar to "I really shouldn't eat that big piece of chocolate cake, it's not good for me, I'm too overweight and don't need it, but I'm going to do it anyway!" Back in the 1980s there was a gourmet brand of ice cream and they ran commercials featuring a very pretty lady sitting there with an empty pint of ice cream telling everyone "I ate ALL of the Fruzen Gladje. And I don't feel the least bit guilty!" Very similar to that (and in fact when that was on TV all the time I'd go around telling myself "I'm 25 years old and I'm wearing smelly, soaking wet diapers! And I don't feel the least bit guilty!"
So is that an AB thing? I personally don't think so, for me the AB thing involves having someone else care for you like you're a baby, changing your diapers, dressing you in baby clothes, the bottle, the paci, playing with baby toys, etc.
But, that being said, I did experiment with that part of it for several years with an ex-girlfriend who for a while let me enjoy my diapers--until she didn't (that story is told elsewhere on the site) and then my wife (mostly in the years before she was my wife). We did the bottle / baby formula / baby food / baby toys thing for a while and while it was fun, I learned that it wasn't what I really enjoyed about this. And several years later when we had kids and REALLY DID have a baby in the house, I then discovered that--for me--all my "fantasies" about being a baby again weren't realistic. Kind of like when you think you're in love with someone only to later get to know them and find out they're not who you dreamed and fantasized that they were.
So since then it's been all about the diapers. Wearing them, using them, getting off in them, filling up the diaper pail with them, smelling them, enjoying the way they feel and smell--along with the notion that I'm a full-grown adult but I still just love wearing DIAPERS!!
But I also have a Nuk 5 pacifier which I love, several baby onesies, very babyish plastic pants, a t-shirt that says "I (HEART) WET STINKY DIAPERS", and other "baby" items. I also sometimes enjoy an occasional visit to the "sissy" side and have a ruffly pink diaper cover, a pink "PAMPERS" shirt and a few other sissy things. It all just depends on what mood I'm in.
And sometimes I'm not in the mood for it at all. It's very much a mild version of the "binge and purge" thing with me (though years ago I learned that when doing the "purge" just box up my "stuff" and put it away, don't get rid of it, because there WILL be a next time). And I find that when I'm stressed or emotionally exhausted I'm drawn to my diapers way more than other times (like right now, dealing with very old parents, I think I've been wearing / sleeping in my diapers 4-5 nights a week because they relax and comfort me).
So, sorry for rambling on and on but I guess the point I'm making is, there are so many different aspects or "flavors" of this wonderful fetish, it's kind of hard to fit some of us into "this category" or "that category". But for the most part I guess that yes, I mostly do like being an ADULT who loves my diapers. I enjoy doing adult things when wearing my diapers. And I enjoy thinking about the humiliation I'd experience if everyone else knew I am an adult who chooses to wear diapers--not because I need them but because I LOVE THEM!