Okay, so in the show Big Bang Theory, we see a lot of couples.
You had Leonard and Penny together for a while. They have since split and Leonard is dating (via long distance) with Raj's sister Priya.
I'm not a big fan of Leonard & Priya, but it works for now.
On the subject of Penny, she should be with either Leonard or (get this) Sheldon. But only under the circumstances that Amy and Sheldon really don't have any sort of future together. It's blatantly obvious that Amy is the female version of Sheldon, but it seems TOO perfect. Like the relationship would be boring, maybe. Or it could work out great and be hilarious. I'd definitely support it, but I think a Penny/Sheldon relationship would be comical as well.
Howard is currently engaged to Bernadette (which I support), however... I feel like if that doesn't work out... maybe Raj and Howard should be together.
Call me crazy, but I see it! It maybe the reason why Raj can't talk to women without being drunk!
Despite what a lot of BBT fans would say, I don't like the idea of a Penny/Raj relationship. It just doesn't sit well with me.
So basically, I think it should be:
Leonard/Penny (Penny should get pregnant at some point with his baby)
Sheldon/Amy
Howard/Bernadette OR Howard/Raj (but I like Bernadette too much to get rid of her, honestly)
Idk what to do with Raj.