How much to tell wife about implant

[Old Guy]

I think what you've got written is great. Yes Peyronies is progressive and can lead to permanent damage. At your age that's not something you want to have over your head, especially if you are planning to marry her.
Once you tell her the issue, and what you've decided to do, let her ask any questions she might have. Some people are put off by medical procedures, blood, etc. Some can handle it.
Good Luck!