Old phone was hacked and now knew phone same person is getting access in EVERYTHING! They know when any passwords get changed but can’t see password but eventually figuring it out through tethering bt and through WiFi routers

How can I get this “firmware” iBoot off my iPhone???? I just got out of a very controlling relationship and previously he some how hacked into my iTunes on my computer. I just got the new iPhone X and still having the same issues. The firmware doesn’t match apple firmware names and I also found logs on his computer he had saved of app activity and phone usage. I had a passcode on my phone but he didn’t know it. So I switched phones thinking it would help but it hasn’t. I knew my husband was in my phone the entire time but I don’t know how to get it off! I know a little about coding and programming due to him doing this to me so I researched and found out allot. I just can’t seem to figure out how to keep him out of my new phone. He’s tracking my location even when location is turned off in all apps and settings. Please can someone help me!