I think I’m becoming too vanilla

My boyfriend of 4 months and I engage in a list of sex, and we’re both sort of switches. I used to think I’m fairly kinky, but going further into this relationship, I feel like I’m sorta losing that. But it’s not him. He always wants to use his belt and stuff, or do knife play, things I used to be into hard, but I often say no now. Sometimes he spanks me when hitting it from the back and I love it. He also chokes me and pulls my hair often, as well as a little name calling, which I enjoy lots. I’ve even suggested getting handcuffs or a whip or the like. I’m not sure if it’s because he just needs to learn how I like it or if my emotional feelings for him prohibit me from wanting to be hurt physically by him now. The sex is always amazing and breath taking but I just feel like I need to let him be kinkier sometimes. Advice?