Could be any number of ailments (more than a few of them serious), so if you have access to a physician, and you don't mind going to one, you should go have a look-see.

Until then, there are other forms of absorbent protection that aren't so noisy. You'd want to look for the ones that are advertised as being "breathable", as they are more quietly cloth-like. Also, from a guy's perspective, they are dramatically more comfortable, as they allow heat to escape better. When I first started having concerns I was using Depends because that's what we all know about and what the stores carry, but they got to be so hot, especially so with a condition I have down yonder, that I just gave up and got a waterproof mattress protector. This meant a lot of laundry, but it was actually more bearable than those crinkly, hot Depends.

Later, the breathable products came out, so I tried them, and they work fairly well. There's the cheap kind, that I tend to use (Attends, Kleinert's), and there's the expensive kind (like Abena and Molicare) that I seldom use, unless I have extra money. They work so well, it's like not having wet at all, but they are 'spensive! The cheap ones leak like crazy, but they keep most of the urine away from the more sensitive parts; plus, I don't have anybody to share my bed with, so that's not much of an issue at this point. Hopefully your wife is as supportive as she says she is and you guys get it all sorted out.

Truth be told, the most economical and comfortable solution is to use night-time weight cloth diapers with a nylon waterproof pant over them. There's a South African company that makes a fastener called a "Snappy" or a "Snappi" that stretches and avoids the embarrassment and the potential blood spillage of giant diaper pins. HOWEVER If you're already beat-down by how you look and feel in a Depend, then an actual traditional diaper set up is not going to help. I only mention it because they are cheaper in the long run, and they hold A LOT. I specifically mention NYLON pants, because it's a whole lot less warm than vinyl or even polyester. Probably less durable, though, but who knows...

But yeah, a cloth set up can hold much more than the best Abena brief -- and those top-tier breathable Abenas, with shipping, come to more than two-dollars per brief! The only real advantage with disposables, besides being semi-convenient for travel (not that bedwetting is even remotely convenient for travelling), is the psychological benefit of being able to throw them out in the morning; of watching your problems go into the bin. Not an insignificant thing, in my opinion... :)

One thing to consider: A nugget of wisdom a lady once gave me (on a forum, I haven't been so fortunate to get such sweet talk from a totally cool bed-partner) -- Women are, for the most part, used to the idea of regularly having fluids come out of their bodies when they don't want them to (menstruation, post-childbirth incontinence, etc... ) and of a need to wear something to catch said fluids for at least a few days each month for a big chunk of their lives. Given that, you sporting an absorbant solution may be less weird to her than you might think. I hope that's the case, anyway! :)

Oh -- and put a cover on that mattress until you get it all figured out! Mattresses ain't cheap, and moving them around can cause injuries that make incontinence worse! With a breathable cover like those made by "Protect A Bed" there's little excuse (besides their being f***ing expensive) to have an uncovered mattress. Hell, even if you dry up again and your wife doesn't have any problems come menopause, they also protect from bugs and dust. It's silly not to have one. Unless you're rich and like to buy new mattresses every week as a weird hobby, of course... :)

I started wetting at night again around 50 years old. It came as quite a shock. I have been told it is something I will have to live with as it is caused by a combination of diabetic nerve damage, a slightly inlarged prostate and an unstable bladder. Please don't let it get you down. If your wife loves you then she will respect you for taking control of the situation. My wife has been very supportive and says it doesn';t worry her one bit and is still happy to sleep with me despite the fact I wet almost every night. I wear tena pads and have kylie under me to catch any leaks so she never gets wet though I have got used to often sleeping in a wet patch if I wet heavily. I can't say it really bothers me now.
When I saw the urologist and the continence nurse they assured me I was far from the only one. There are many many adults who wet the bed and sone have never been dry at night where as others have started wetting again a lot younger than middle age.