Definitely isn't vanilla. Dude was rejected by her and now when she has issues with her boyfriend she comes around? Just for the sex and food? Great art. Good story. Not vanilla. Just raw lust.
To be honest, I'm kind of doubtful about that Vanilla tag. If she broke it off with her boyfriend for him, then okay, that'd work, but...She mentions that she rejected him because if he ever rejected her, she couldn't bear it even more than being with her current insufferable boyfriend?
Seriously? I think this transcends the realm of Tsundere. I doubt he'd ever do that to her, and you'd think she'd know that.
I'd feel bad for him, but I guess he seems kind of alright with this arrangement.