So you've been with your wife a long time, you love her and jealousy has never been an issue before. The fact that this is out of character for your wife, suggests something feels ‘different’ to her regards this friendship. It's not sitting right with her.
Now perhaps it's nothing and her gut is wrong, but perhaps she knows you well and has for many years and can see something different in you with this friendship.
You might protest and think she's being unreasonable because it's ‘just’ a friendship, but even if that's true and she's being unreasonable, I think showing some grace, when she's generally and not typically unreasonable, is what’s needed.
I'm not jealous as a rule, but many years ago my husband had a female boss and I joined them on a night out. I had this overwhelming gut instinct that she was attracted to my husband and I felt threatened and jealous. I told my husband, he said he didn't think that was the case, but because it upset me, he said he wouldn't go on any more work nights out. That was that. Maybe I was being ‘crazy’ but I so appreciated my husband treating me like I wasn't.
That in the ONLY time in our whole marriage I've felt that way. I think we should all be allowed a pass for one-off gut feelings.
If it's ‘just’ a friendship (and a relatively new one at that), your wife’s feelings should easily be the priority and either distracting or ending the friendship shouldn't be too much of a thing.