Puck/Santana works for me. I'll have to make another account cause both of mine are in use, so I'll let you know once I do.
Here's my understanding of their relationship, though I'm open to other opinions:
Puck and Santana were dating pre-canon through episode 3 (how long is uncertain). I could see it being a long-standing on-again, off-again thing. Though I also see their relationship being unconventional. They never slept together, but Santana is certainly not a virgin. She probably slept with other guys (and Brittany) but kept their relationship to dirty talk/sexting for the benefit of her facade in the celibacy club. He obviously cheated too seeing as he got Quinn pregnant.
As for after she broke up with him, I see her dating around a lot but as soon as he expresses interest in anyone (i.e. Rachel, Quinn, Mercedes) the claws come out and she suddenly has an interest in him again. Basically because she doesn't want him with anyone else, like she stakes her claim in him even when they're not together.