AITA for using an adult toy after my boyfriend asked me not to?

Throwaway for obvious reasons. I (22F) have been dating my boyfriend (26M) for the past seven months. He is sweet, handsome, and very caring, but try as he might, he cannot make me come. After sex, he likes to take a shower before joining me in bed (I take mine the morning after), and in that time I use toys to satisfy myself. I never told him this, as I didn't think he would care, but about a month ago he found out and asked me to stop. He said it makes him insecure that he can't make me finish, and said that me using an adult toy makes him even more embarrassed. I stopped for a little while, but I began using it again recently. Yesterday, after sex, he got out of his shower early and walked in on me. We had a fight and I told him he was being selfish for only prioritizing his pleasure during sex. He told me that I was the selfish one for putting my desires over his feelings. While we have calmed down since, neither of us have apologized. I talked to my friends and they seem split on the issue. So Reddit, am I the asshole?