What do you think about me wearing my girlfriend's gift to the gym?
Do you really like her gift that much?
I like the gift but I want our relationship operate on looser structure
It would probably be better to get your girlfriend gifts that she can use instead of you. This way she knows that you purchased the gift solely for her happiness.
I can do whatever I want with a gift I bought.
If the gift was hers, she would probably appreciate it if you asked her before using it. This would be the more respectful approach.