How can I get sole custody and get rid of shared parenting in Ohio?

My ex husband and I got a divorce a year and a half ago. I am custodial and residential parent and he is non-residential parent. In Ohio, we have what is shared parenting so he can be included on major decisions but in the paperwork I have the last say. My question is how do I get sole custody? He has a say in whether I can move even to another county let alone another state. He does not take our son over night and has only had him over night maybe once in the last 10 months. He only takes our son when it is convenient for him and works with his work schedule and never follows the agreement. He harasses me and says that I have to ask him first if I use a babysitter and he doesn't even pay for it, let alone daycare!! He is 1300 dollars behind on his child support and will go thru spurts of not paying for 4 months. He calls and harasses me at work screaming obscenities over a pair of $15 dollar shoes he bought that were ruined by our new puppy demanding the money. He will cuss and call me names on the phone while I am at work. I had to change my cell phone number because he wouldn't stop leaving disgusting sexual messages/texts and now is threatening to take me to court if I do not give it to him. I in no way want to not let my son see his father or take that away from him but I do everything myself and would like to be able to move one day. Any advice?