Partner always think he doing something wrong.

My partner and I had sex a couple of time, I want to try kinky sex like choking, hair pulling, being tied down, etc.. but he thinks that he doing something wrong if something off. He was deep throating me one time and my eyes were watering (but he didn’t know that) when he was doing me from behind and started to see me spotting a little, he freaked out and when he started to talk to me my voice was cracking a little. So he thought he was doing something wrong and doesn’t get to the point of being kinky. I don’t know what to do about this situation because I don’t want him not to do any of the kinky stuff that we want to do if he going to think he doing something wrong for something so little.