Sex can be a part of a loving relationship but it can also be used to bargain with. When there is little more than an exchange of flirting fun and physical interaction with each other this is not the same thing as love. Love has to also have a basis of respectful friendship as well. And if two years have been going on and this man can come and go as he pleases, or tell you some (likely made up) story as to why he needs to break up with you; or worse blame you for this then you would be doing yourself a huge favourite if the next time this happens you simply agree with him and walk away, end of story.

He is hurting you by the sound of it, over and over again. If a man wanted to really be with you then he would and he would stick around long enough to try and work things out before he gave up. This is not the same, by the sound of it, by a long shot. He sounds like he makes excuses to win you over so he can just have sex for a little while. Let him go and let your heart heal so it can open again for someone who will be much healthier towards you. Allowing yourself to have repetitive cycles of hurt by this boy will only slow you down from meeting a real man who wants you for who you are as a whole person sexually, emotionally, intellectually and spritually.. Take care