When he tells her the first time, he's drunk.
And of course he's drunk, because it's three in the morning and the scotch wasn't gone yet and he's Tony Stark, so it's basically just a force of habit. Pepper's used to it, though. She's used to finding him stumbling over the bar in the basement with the taste of liquor on his breath, and she's used to somehow getting him back up to bed, making sure he's not going to get sick and tucking him in, just because she knows he won't remember it in the morning. It sucks, and it wasn't anywhere in the paperwork when she signed up to be his PA, but she's used to it.
She's also used to finding him the morning after, skin all pale with dark circles under his eyes, downing coffee like it's all he needs to survive right then. She's used to knowing that he would have absolutely no idea what he did the night before, what he said, or how she took care of him, just like she always did.
So the first time he tells her, he doesn't remember.
It's about twenty after three in the morning, and Pepper's finally managed to get him into bed well enough that he isn't going to fall off and knock over the glass of ice water she's set on the bedside table. Tony's passed out, or at least she thinks he is, so she's leaving, hoping that she'd get at least two hours of uninterrupted sleep that night. Until she realizes he's not passed out, just on the verge of it, punctuated by four little words that somebody normal wouldn't have understood, but Pepper's used to listening to Tony's drunken rambles, so she can.
"I love you, Pep."
She stops in her tracks, a manicured hand just barely touching the doorknob when she hears him. No, she thinks, no, he doesn't mean it, he's just drunk. He's said a lot of silly things while he's drunk, pulled stupid faces, maybe tried to make a move on her once or twice. She knows he doesn't mean any of it because his mind is trapped in some foggy haze that he'll be regretting in the morning, knows that it's just the way she always covers his ass that he loves, not her.
But she stops anyway.
She doesn't know why she stops. She shouldn't, because what she needs is sleep, a few hours to forget everything just like Tony can, and what she doesn't need is this. This… this conflict, these feelings, that little shred of optimism that maybe he does mean it and he's just hiding behind the drunken persona to admit it because, contrary to popular belief, some things do actually scare Tony Stark.
Maybe she stops because she knows that's just ridiculous wishful thinking.
Maybe she stops because she loves him, too.
She stops, but it's only for a moment. Just a brief, fleeting moment that she lets herself bask in the warmth of those four little words that slipped from Tony's slurred tongue before she forces herself to leave, tells herself it's not worth it.
When he tells her the first time, he doesn't remember.
But she does.
When he tells her the second time, he's not drunk.
And of course he's not drunk, because it's seven in the evening and they're on a date and like hell he would screw that up just by getting drunk. Pepper's almost used to this, too. It's been months since that kiss on the rooftop and years since that night when he'd told her the first time, and she's almost gotten used to being in his arms, him protecting her just like she always used to protect him.
It's just about quarter after seven in the evening, and it's November, so the stars are in the sky by now. Her head is on his chest just above the soft glow of the arc reactor, and his suit jacket is around her shoulders because it's just a little bit chilly that night. She's still mostly comfortable though, but she's not quite sure if he is so she lifts her head to ask, the question almost leaving her lips until she sees the glint in his big, inky eyes as he looks down at her.
Tony's an honest man. Pepper knows that. She knows that he's honest in his own snarky, biting way, she knows he's honest even when he shouldn't be, she knows he's honest most of all when he's drunk. Tony's not a perfect man, but he's an honest one, and she silently scolds herself for thinking, even if only for that little fleeting moment years and years ago, that he wasn't.
So he meant it. Maybe he doesn't remember it, but he meant it.
But he says it a second time, anyway. Just for good measure.
"I love you, Pep."
And when he tells her the second time, they both remember it.