I think there is no point beating around the bush, you should straightway tell him that you don't feel loved and comfortable in this relationship, you guys are not able to grow together in this, that's why it's better to part ways.
if you live with him make arrangement for somewhere else to go, tell him your leaving and stick to what your saying no matter what he says or does.
if you dont live with him have a friend come stay for a couple of days for support if you need,tell him your reasons you dont want to be with him end the relationship and take some space for yourself and to give him some time to realize you arnt coming back.
i just think you need to be completely open and honest with him and do what you need to for you too
just be strong and take ur step which makes u feel good
make ur statement straight on him