BDSM isn't what has damaged your wife.
Your wife's poor (even perhaps reprehensible) choices and significant negligence are what has damaged your wife.
As others have suggested, maybe there was abuse in the relationship with the bf, maybe not. The specific acts you have described are potentially within the realm of safe, sane, consentual BDSM. Heck, I know several online stores, and a couple brick-and-mortar shops, where one can easily purchase the hook you describe. I can think of three different types off the top of my head, even. I wouldn't mind having one.
I'll grant, calling someone asswhore or such things isn't my cup of tea, but some folks like it.
I don't advise showing photos to the mother not because there's anything wrong with BDSM (there isn't), but because it would be hurtful and shaming to show ANY photo of your wife in ANY sex act to her mother. Do you think blowjobs are sick and wrong? When your daughter is an adult, will she want her husband showing YOU a photo of her giving him a blowjob?
Shaming someone who is suicidally depressed is a Very Bad Idea, if you want them not to commit suicide.
Of course, I think your wife was quite stupid to allow such photos to be taken, anyway. And even more stupid to keep them around. And, of course, distressingly negligent in leaving access to them.
I think it would behoove you to read and re-read NeonChaos' recent posts, as objectively as you can. There's some harsh truth for you.