Give him the phone back. You can buy a cheap phone or save up for a better one. As for the family, I am sure they will understand.
Unless you were horrible to him... but I think you will probably be forgotten as time goes on. That's life. People move on. If you are really sure about leaving him, and you think you can't make it work, just do it. Don't waste your time or his. Have a talk with him. Don't get loud or overly emotional. Make him understand why and don't let him talk you out of it. You will feel like you are making a mistake, but things will get better. I know it sucks because you invested years in this relationship for it to end like this. It's going to be hard to let go. But trust me, being in an unhappy relationship is not good for your mental health. Stay strong. You can do it. Think about your future and how your life will be better without him. Sound harsh, but that's reality.
I had a similar experience as well. I stayed with him because was worried for him and liked his family.
I was in a relationship for 5 years. We lived together for 2 years. He changed so much. I wanted to break up with him, but I couldn't because of guilt. He moved into my apartment and left London for me. I felt bad and wonder what will happen to him. I stayed with him...even though I was unhappy. I wanted to make it work badly. I kept making excuses for him. In the end, It didn't solve anything. When I finally got the courage, I told I wanted to break up. I reached my breaking point. I couldn't do this anymore. I gave him one week to leave my place, which was of course sad, but I was hopeful. There was a moment when I felt I was making a mistake. But still, I never took my word back. I stayed strong. We were amicable the whole week. I helped him pack his things. I cried my eyes out the day he left. I felt weird living alone. But eventually, I got used to it. It took me a few months to realise it was the best decision I ever made. I wish I had done it earlier.