Based on those texts, it appear she's ready to consider moving it from fantasy to reality. She didn't commit, but she essentially said she's willing to try, because she wants to make you happy (a common reason many wives try it the first time). You have one chance to do it right and enter the lifestyle for real.
If you're asking for advice I would suggest making sure that you talk constantly as you start moving forward. No detail is too minor. Arrange the entire thing based on HER wants and preferences. Make it all about her, and her pleasure. Listen to what she says. A perfect example is above... she said it's easier for her to talk about this using texts, so DO THAT. Use a lot of texts in addition to talking.
Every husband has a fantasy scene they want to see. Forget your fantasy. It's HER fantasy that matters. Let her decide all the details... how you find the guy (alone or together)... let her pick the guy (she's fucking him, you're not!)... where it happens... when it happens... what they do, and how you fit in... all of that needs to be HER decision. No matter what she decides, you need to agree and support everything.
Also, even though she seems ready to move forward, don't rush her. She's going to be nervous. Let her set the pace. Everyone moves at different speeds, and women usually move slower than us guys. It could still take months. If you push her you risk blowing things up, so be patient. Good luck!
cuckold - Pronunciation - kuk-uhld - noun 1) The husband of an unfaithful wife. 2) A husband whose wife has sex with others. NOTE - It does NOT say: Sexually confused, submissive, humiliated, sissified, crossdresser, cocksucker, or piss drinker