Hacked

If your iPhone has not been jailbroken, it has not been hacked. However, accounts can be compromised, as well as your Apple ID. See this if you believe your Apple ID had been compromised. If you think your Apple ID has been compromised - Apple Support Otherwise, what makes you feel your device has been hacked?

It would take someone having possession of the phone for an extended period of time, jailbreaking the device, knowing your Apple ID and password, and then installing software. I doubt that has been the case.

I suggest talking to him then if you feel that is the case. As far as the phone is concerned, you can restore it to factory and set it up as new. Do not use a backup.

Anyone who knows your Apple ID and password can see your texts. And just about everything else that you sync to iCloud.