If you truly do not want to be in the relationship anymore you need to break up with him while he is in jail so that you can move on without his interference if you feel like he wouldn't allow you to do so if he were free, then do it while he is gone, write him a letter telling how you feel and how you have been feeling about the relationship and if you are not happy then you should tell him that and tell him you haven't been happy for a while. The fact that he didn't say I love you and apologize when he was free to do so shows you that he is doing what some people call "jail or prison talk" he has nothing better to do but still around ponder how he treated you and feels insecure about you being free to do what you want to do now.
If you're going to break free you should do it now so that you can truly start with a clean slate. How long is he going to be in jail? This too can influence how and when you tell him that you want to move on but if you seriously want to do this it has to be done now before he gets out and can possibly influence your decision. Most time the things they say in jail is just talk and when they finally get out more times then none they are the same as before they were incarcerated and you find that you have wasted alot of time waiting for them only to see that they haven't changed at all.
The final decision as to how you tell him is up to you but with every relationship when it is through someone gets hurt it's just part of human nature so you can not worry about hurting him it will hurt no matter whether he were in jail or face to face, just remember this is something you have to want for yourself to make you happy and if being without him will make you happy then this is something you have to do for you. Break ups are not happy times and hurt there is no way you can break off a relationship without hurting someone feelings all you can do is be honest with the way you feel about the relationship and relay this to him and tell him that you want more from a relationship and feel you deserve more than what he has given you. If possible you may need to change your number and move if he has made the comment that if you weren't his you weren't going to be no ones shows that if worse comes to worse and he continues to threaten you maybe you should go to court and get a restraining order if he is making threats from jail that could possibly warrant him getting more time but I am not a legal expert so I don't know for sure you would have to ask one of our legal experts at Just Answer they would have the answer to that question for you. If you have anything to add or anything else you want to mention about your situation click reply it is free.