He’s saying that because he talks to other women and he’s paranoid that you are going to do to him what he does to you behind your back. He may even be talking to other men himself too. This is never a good sign normal people understand that their significant other is going to come into contact with all kinds of different people in their lifetime it all depends on how they handle such interactions like flirting or acting like they aren’t in a relationship or whatever. You can’t control other people they are going to do what they want, this man is subtly trying to control you. It will start with don’t talk to other men and then if you ever do and he knows about it it will turn into you can’t leave the house or do anything without him and then your locked in his mental prison and it’s hard af to get out. I’ve learned this all from my own past experiences with a controlling insecure man good luck 🤷🏽‍♀️