Another reason why I think it's unlikely Reeva was about to dump OP is because she'd already mentioned in a text that she was scared of him sometimes and how he would react to her. Reeva wasn't stupid. I'm sure she knew that dumping him after a) giving him a Valentine's Day gift, b) cooking him dinner (if that's what happened) and c) changing her plans to go home - was going to invoke some sort of unpleasant response from OP. Why would she risk that when we know she was always on tiptoes round him to avoid offending him about anything, chewing gum, hair in a ponytail, talking to a waiter for too long, dressed too casually etc etc. It's just not feasible that she'd risk a negative reaction to such a significant issue when she was on her own with him.
She did what every DV victim does.
She underestimated the danger she was in.
Or, it was an accident.