Need to vent before it becomes toxic jealousy

I introduced my 'adopted' daughter Zeta to O a few days ago. I knew they'd hit it off, knew they'd get along, knew it down to my core. So why, now, am I being flooded with rioting levels of jealousy. I told her about him, explained some of his complexities (not all of them, some of the things he's revealed to me are protected by the unsworn HIPAA code) so she knew who she was meeting.

He likes her directness and bluntness. I knew they'd get along, knew he'd be drawn to her. Figured it would either go really well or blow up warhead style. So why does the idea of them getting along stir up that ugly green monster? She knows what I feel for him, at least enough to know I'm interested, and she has a guy-not a great guy (any more than mine is). But that green beast lifts its head whenever he mentions her (which isn't often, right now) and growls a deeply possessive protective growl that isn't even my right to feel. He's 'mine' not to own, but to love alone; and little else so long as I remain married to E - and I know this yet that damn growl rumbles through my mind, my heart, my soul. I don't feel threatened by her, but that beast still growls. If he falls for her and it makes him happy when I cannot - ill cope with the beast because I only want him to be happy - damn my own happiness.

So why does saying that hurt so much? I want him happy, I want him to be mine in every way imaginable -- but I need him to be happy, and if it's not with me, so be it.

My Wolf!! My Wolf, who stalks the forests of my mind, even as the dragon used to..  He is mine, but his happiness is all that matters.

I get that I don't need to feel this way, but emotions are never logical.