My advice is to do all the preparation work first and slow your roll.

There are so many things you have to do before that even should be considered a possibility.

You should be asking what can I do to be as prepared as possible for IF my wife decides to actually do it?

Might want to think about how to assess if your relationship is really ready for it.

How to solidify communication?

How to pick a playpartner together?

Maybe read up on Poly and ENM?

Talk to a kink friendly therapist BEFORE you get into this so that you can understand reasonable expectations and get solid guidance on it?

https://www.kapprofessionals.org/business-directory-2/

Maybe ask for books you can read on ethical non-monogamy and poly? Cause that's what you'd be doing. "Polysecure" by Jessica Fern is a good place to start btw.

I know you aren't ready because you aren't discussing what you've done to prepare for this to occur, you're looking for advice on how to MAKE it occur.

It isn't going to happen unless the woman wants to do it. That means finding the right bull/lover/3rd and taking your time. It also means be prepared for it. It's much more enjoyable when you've done everything you can to make it success.

I wish you luck. Do the work upfront and avoid the tears on the back end.