Giving gifts to my boyfriend?

My boyfriend is incredibly generous, he always gets me gifts (almost every week). I never asked him for gifts, and I even told him that although I appreciate it, he really doesn't have to do it. He said that it makes him happy. My question is, do I have to give him back a gift every time he gifts something? I feel really uncomfortable just saying thank you, I feel like it's not enough, but I don't know what to do. What's the proper etiquette in this situation?

Giving gifts to my boyfriend?
Post Opinion