Love Him or Leave Him

If you spend all of your time together, then he knows you are not cheating.

I suggest you let him know that his behavior is fast becoming a 'deal breaker' for you. He needs to know that his accusations will lead you to end the relationship if they keep up.

If he agrees that his accusations are unwarranted, yet cannot stop making them of his own accord, then individual counseling is in order. If he isn't willing to take that step, then I think it's only a matter of time before you walk out the door.

Jkgrandma gave you an excellent answer (thumb up).  There is another possibility: He doesn't want to take your relation one step higher and that's his "aliby / excuse" not to do it.

It may be that he cannot help himself. You may realise that when it is too late (after marriage, baby, violent outburst or stalking). This is a tough decision, but it is a necessary decision. You know if he is being abnormally obsessive and then you know what you have to do

Follow your heart, but let your mind read the signs

the need to feel control over your everyday life to insure himself of your fidelity is called a compulsion.this stems from a deep seated fear of abandonment.also impulse control can have to do with serious personalitiy disorders.i would suggest counseling for you both.at least look into the compulsion aspect.good luck