It was a very young relationship, they had no commitments together as of yet, no children, not dependant on each other financially, no reason to stay if you didn't want to, and Reeva had been in a bad relationship before, so would have had some wisdom there. As to him not saying he loved her via a card or present, someone always has to say it first in a relationship, it doesn't mean it's not reciprocated..it's a scary thing to say..and on the issue of it being thoughtless that he didn't get a present etc, Oscar would not be the first man to underestimate the importance of these things to a lady.
Normally I would totally agree, but you forget the whatsapp message she had sent him... telling him she was ready to tell him how she felt, it was a headsup and he didn't "get it"...