On my second playthrough I had a bug with Leliana, who was convinced I was romancing her. I wasn't even nice to her (Aedan Cousland was an asshole to pretty much everyone) so I don't understand how that even happened. But I had to dump her... twice, because apparently being dumped in an imaginary relationship doesn't end the relationship. And yet in the end Leliana starts asking awkward questions about what is going to happen to them now that he's going to marry Anora.
Zevran, meanwhile, was the coolest boyfriend and totally chill with being the prince consort (king)'s lover and royal assassin. To be fair, it's a pretty sweet deal all things considered.
Silly girl. She should have known that Zevran is simply irressitable to the majority of DA players.
I had the same situation with Zevran. Well, maybe similiar. I was romancing Alistair from the very beginning and then, at one point near the end he was all like "Why are you flirting with Zevran? You have to choose between us". I was pretty much surpised, because I hadn't romanced Zevran at all. And Zevran was then "You don't have to hide it, I see you have something with Alistair". No duh, I was sharing his tent when I met Zevran already. And then he was -25 frienship :( .
It gets really bad if you end up using the gifts from the Feastday DLC, because if you get their approval too high, too quickly, it prevents you from getting certain pieces of dialogue, and everyone thinks they're in a relationship with you. At least that happened when I last used it.
I had something similar once haha
I had to "break up" with her to stay with Zev, it was weird. At least it wasn't just me, though.
It happens every play through with me. If I get high approval with her, I have to dump her twice.
My Tabris had the same thing except it was Alistair whom Leliana was jealous of.
Jist of one conversation: Tabris: I'd rather just be friends
Jist of the next:
Leliana:But you said you loved me!
On the other subject of discussion: I've actually never found any appeal in Zevran myself.