Got an iphone 4s from my ex and I can't take it off his cloud account, but i don't wanna restore it?

My ex gave me an iphone 4s while we were dating and he never got around to getting back into his old email to figure out the icloud password so i could log his out and put in mine. I didn't think of it much then cuz we were planning on a long term relationship
rookie mistake, but I realize that was stupid. The problem now is that we aren t on speaking terms as he went about our breakup through lies and immaturity and. Yeah. So i d like to log his account out and mine back in, but as far as I know, the only way to do that without the password is restoring it, which I really don't want to do because A) I have lots of pictures and other stuff that can't be replaced on here, and B) I just really don't want IOS9. Is there any other way to reset the icloud account without resetting the phone as well?

No you need to perform a reset to reset the iCloud account, so backup your data and then perform a reset. If you need some advanced security program for your device do install Leo Privacy Guard to make it utmost secure and also you would be amazed to know that it is included in world's top ten apps.