After Nancy breaking up with him and getting with Jonathan, and a string of dates who only uses him for sex before moving on, Steve starts to feel like he's unlovable, that there's something so wrong with him that no one could ever love him.
He tries going out with men, but they just use him for sex as well.
And he feels so empty, he just gives up and lets himself be used by anyone, thinking that's all he's worth.
To the point where he just checks out, and has no idea who or how many who's with him. He gets a reputation for being easy, and people no longer bother asking for his consent, because he just lets it happen.

Nancy (or Nancy and Jonathan) discovers him with someone, they apologize for the interruption and are about to leave him to it, when they discovers that he's completely out of it and non responsive.
They stop what's happening and take him to a safe space.

Steve admits to what he's been feeling, and what has been happening to him, and Nancy (or N&J) confesses that they love him, but that they thought he lived a happy single life and were afraid of rejection after the way they had hurt him.

And then they get together... and they make love

PS: No AIDS for Steve, that would be too depressing, he's either super, super lucky, or everyone who was with him decided to wrap it up for their own safety knowing Steve's reputation, or maybe this is a world where STDs doesn't exist, up to you