Polls: Marriage & Weddings

My mom got upset at my boyfriend for proposing to me with a cheap ring. It was so much drama we called off the engagement for a while. My mom nagged me about how it didn't even look like an engagement ring( it had a sapphire in the middle instead of a diamond, my boyfriend asked me if I wanted his birthstone and I said yes but I meant on the sides, lol) . Days had passed and my boyfriend asked me for an example of the ring I would want. And I showed him this one

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I showed my mom the same ring and she thought it was pretty until she saw the price and went on nagging about how cheap it was and how I'm selling myself short and if he can't afford better he doesn't deserve me. I'm hurt and confused as to why this little symbol is such a big deal. I'm I selling myself short to not care as much for the ring?