you really really really need to think about this reasons thoroughly because you just don't want to break up with someone when later on you realize this reasons weren't worthwhile after all. I mean you love her/him after all. I'm not trying to stop you, i just want you to think it through because you really don't want to throw away your love if the reasons aren't that good. But if you still want to leave but still love her/him then i suggest you have to break up with them and take things slowly, i mean it isn't very easy to just one day for your love to fade away. You have to at least take advantage of this reasons and keep reminding yourself why you broke up with her/him. Make sure its not something you regret. Smile when you think of her/him, don't struggle too much. Just keep on living and do your usual routines. Think of something else when you think you just can't stop thinking about her/him or think of someone else. Keep yourself busy when you start to feel lonely or if you start regretting. its not easy to forget abotu how you feel, but this is what you want and you should be happy.