You're used to it, by now.
That twinge of pain you used to feel when he brought another one home is a distant memory. Has been for a while. They're his playthings, pretty little faces and bodies like Adonis and Aphrodite and no brain whatsoever, and they don't mean anything. He's careful about his health and uses protection, and that's the only thing you really care about. You're the one he relies on, the one without whom he is literally helpless, the constant in his equation of ever-changing variables. You know exactly where you stand with him, and where you stand with him is right beside him. At eye level. And sometimes above.
He needs you, not just any assistant but you, because you are organized and capable, but mainly because you know him better than he knows himself. Because you know that he wakes up late on Wednesdays and how much scotch he wants when he's low and yes, even when he hasn't eaten well in a couple of days and might need an extra bran muffin or a scoop of Metamucil in his juice. You're part of him. And despite your initial efforts to keep your personal life separate from your work life, he's part of you.
At some point along the way, you got so tangled up, so twined with him, that neither one of you can function without the other. Which is why the playthings don't matter.
But this -
This is different.
Because Bruce isn't a plaything. Isn't a one-night stand. Tony won't wake up at five AM and sneak out of the bedroom after a tumble in the sheets, leaving you to show Bruce out. No. You knew it as soon as he introduced you; knew it before, even. Because you saw the way Tony looked at Bruce, and it wasn't with aesthetic appreciation or attraction or even lust. It was the awed, openmouthed gaze of a man who has finally found an equal. And then you looked at Bruce and you saw at once that he wanted Tony right back.
You knew this moment would come eventually. Had to, with Phil and Fury breathing down Tony's neck to cooperate with S.H.I.E.L.D. It was only a matter of time before he met a mind as great as his.
You just hadn't thought it would be this soon.
Bruce is shy and sweet, all awkward smiles and oversized hands, and once he opened his mouth and spoke, you could see why Tony fell for him. No one wouldn't. You know about the Hulk thing, about what happens when he loses control, but you can't quite believe it. Not that it matters, anyway, because Tony obviously adores him. You just wonder how long it will take Tony to figure it out.
When Tony said "We're going for dinner," you know that Bruce will be with him when he comes back.
He is, of course.
So you make them coffee, and straighten the wreckage of the living room, and help them nail plastic sheeting over the broken windows; and then, as they sit together at the bar, heads close, talking fervently, you slip away.
And because you love him as you love yourself, you fold your hands, and close your eyes, and begin to extract Tony Stark from your heart.