Feeling rejected

My boyfriend of 7 years is so loving and caring but at times he pushes me away. I do not know what to think or how should i feel, of late our sex life is not to good. When i try being intimate with him he is always tired or has pain or some excuse. I am really tired and frustrated about this cause am a woman i do have needs, wheh he is in the mood he gets but when am in the mood is no. What should i do about it, i tryed talking to him about it but is the dame story again and again. He will try and improve but time pass and is the samr nothing. Its months now we have not have sex and i worried whats happening to us.