How can I let go for good and move on when it seems impossible...please help me?

He is NOT going to change. Are you prepared for a life of this kind of defensive living because it will only become more pronounced in your relationship. Jealousy and possessiveness are deal breakers because although you think it's because he just loves you soooo much, it's really because he has such low self esteem and is looking to you for his self worth. Trust me, your sick of the situation now? just wait a few more years...ugh