Boyfriend bought his ex a necklace and i'm getting gift cards?

I'm not usually the selfish or jealous type so i'm unsure why this has been on my mind or bothering me lately. But a month or so ago was my boyfriend's birthday. he turned 25 and i'm 20. we have been together for about 8 months now. after i gave him all his gifts he made a comment that went something like "i hope you realize i'm not much of a shopper, i'll probably end up giving you cash or gift cards as gifts" and started laughing. he was serious though and i really never cared, i honestly thought it was funny. But about two days ago I found a beautiful expensive necklace in his room that was broken in a box. out of curiosity (because i'm a girl and do crazy things sometimes) i looked at his ex's facebook and it was her necklace... 4 months into them dating. I asked him about it and he did tell me that it was a necklace he gave to his ex. I know it's a selfish thing to say, but is it bad that if he gave me gift cards for Christmas i would be upset? just because after 4 months of dating he bought her a beautiful expensive necklace and we have been together 8 months and he told me he was getting me gift cards.. is it bad to be bothered by this? guys, why would he do this?
Boyfriend bought his ex a necklace and i'm getting gift cards?
Post Opinion