When?

When do you do know when you shouldn't be in a relationship anymore ...what do you do when you just have no more interest in a relationship anymore but it's kind of hard to get out of it because my boyfriend is so committed to our relationship he doesn't want us to break up ..I've tried so many times ...but he loves me so much he want me to the girl he marries I love him but I just don't feel the same way I did when we first started dating ...I feel like we became more distant but we are also okay not being together everyday as much as we used to