>I don't want to end my marriage, by any stretch, but I know beyond a doubt that my wife would not be open to that kind of relationship

And there it is. You made a monogamous vow to someone, for better or worse, till death do you part. To her alone. And she did for you. Yes?

If you suddenly want to change the basic tenets of that agreement, and she does not, then you're looking at divorce. I mean, it's that simple.

​

>she had feelings for him, and she backed way off and ended that friendship on her own accord. She never hid anything from me, and at worst it got borderline flirtatious...

So... she's a good person, and knows how to deal with passing crushes like a mature married person.

There is so much more to polyamory than the supposed permission to sleep with your random crushes. It's sad to watch these middle aged people leave happy fulfilling marriages in pursuit of greener pastures, claiming a newfound interest in 'polyamory', only to be slapped with reality the second they actually try to pursue these passing interests.

That barista is likely just being nice- it is likely she does not want to sleep with you. You're just going through a panic at 34 imagining all the women you could be sleeping with, not realizing your best case end-goal would be to find an amazing woman to marry. ....Like you already have.

Sounds to me like you're hitting your midlife crisis a little early tbh.