He knows it's crazy this thing he had, has with Lauren. It's just she's not a part of any of it. He's never really done the whole dating thing where you know, you wait to sleep with the girl till you know her. The closest he's come is that week with Berry and only because Santana was acting Loca and wouldn't give it up. Girls have always come easy for him, and quick if he does say so himself. But they don't last (not to say he can't last, he's golden on stamina). But it's different now. He's got a daughter out there, and he just can't look at girls the same. Because suddenly there all someone's daughter and he would want to kill anyone who had sex with his daughter and then was gone before the sweat had even dried (he's terrified she'll be like Quinn and meet someone like him). So yeah, things are different. He's trying, but the only girls he knows like the names of reliably are the girls in Glee. And he's just . . .over it. Because despite having his baby, Quinn is Finn's. Rachel is definitely Finn's, despite the shared religion and him being her first boyfriend and actually being halfway decent at it among some other things. Santana's mostly free but there's so much history and he's just not sure they can be more than benefits, besides she's kinda trying to do something with Sam. Brittany and Goth girl are taken. And Mercedes. . .well he's just not going there again. Which leaves Lauren, and no she's not what he ever wanted before and maybe he doesn't want her now, but she's not in the pentagon-hexagon-whateveragon that has Finn and Quinn at it's center. He's done being in it too.
There is someone he does kind of want. But he's not sure why. He knows he tends to be kinder with her. Like her calling him Noah, makes him act less like Puck around her. She's just so embroiled in the Finn affair that he's not even willing to try. And yeah, he forgets his resolve when she pays him any attention and can't quite resist her lips when she's offering, but he's not chasing her. Because Beth made him think about girls as more than just a warm body, and he's not sure if the only reason he wants her is because he hasn't had her. So he won't seduce her away, just to abandon her (like Jesse and Finn have). He's trying to be better. He thinks better might involve being her friend, like for real, and wanting Lauren. Because yeah, girls' not gonna do anything but string him along, but it's good practice for another high maintenance girl. One who he's gonna want to make out with (at the least) a lot more.
Thing about Lauren is she also kind of prepares him for when that other girl uses him. Cause Lauren demands never have a reward or even praise. And the other girl only sees him when she needs someone to make Finn jealous- be that to sing with or make out with. So maybe Lauren's daily reminders that he's not good enough, make Berry's use of him sting a little less. He thinks he may also be the good looking best friend, awesome to make you feel good or your boyfriend jealous but that no one really wants to keep around long-term. Question is now that he's seeing girls as more, what's so wrong with him that they don't see the same?
So yeah, he knows people don't expect the Lauren thing. But really who else is there?
AN: I just need to explain the Lauren thing in my own mind. Besides I think there is more to Puck than we see.