Should I be upset?

Okay, ladies. So I’ve been with my boyfriend for almost a year now and we don’t remember what day we started dating. Now we’re both the sentimental type so we were a little sad about this. So then he decided since it was some day in January we’d make it New Year’s Day. At least that day was near the date we started dating and New Year’s is a fun holiday. For back story on what happens next he was dating someone else a couple weeks before we started dating and he had been dating her for four years. She cheated on him several times and then a week after they broke up she slept with his best friend. Also they were still dating on New Year’s last year. So tonight my s/o started telling me that it would be disrespectful to do it because he was still dating this other girl then and the happy anniversary posts might hurt her feelings. I would be more understanding if he were trying to be respectful of her if they ended amicably. But I was SO excited to have it on New Year’s and now I’m disappointed because he wants to bend over backwards for a girl that treated him like shit, has tried to meddle in our relationship, and she’s moved on now! When we first started dating I was completely understanding of wanting to not hurt her feelings so I didn’t post a lot about him and all that but IT HAS BEEN A YEAR