Frustrated

My boyfriend and I have been together a little over 3 and a half years. Im 28 and hes 34. I know I have a higher sex drive than him and have been okay with it. Some times we can have sex any where between 2-3 times a week and then have a dry spell for 2-3 weeks . We both work and Im trying to be understanding but when Im in the mood Im in the mood. Ive talked to him about it and he does okay for a while and then its back to it. I feel bad and almost like am addict because I do enjoy when we are together but this inconsistency is killing me. Masterbateing helps from time to time but I just want more consistency with him. Help!!!