After three years together he should know that you take even this non marital "anniversary" seriously. So even if he thinks it's silly he should at least recognize that it's important you. These are the compromises we're supposed to make when we're in a relationship. So now you know that he doesn't prioritize sentimentality. But the truth is you've probably known that for a while now. All you can really do is decide if the positives he brings to the relationship outweigh what you perceive as the negatives. Once the bad eclipses the good there's not much to do but consider ending the relationship.