Wow, is all I can say. This is like - amazing. Your letter is amazing - I will treasure it. Yes I believe him totally. Yes - believe him about everything. What happened in terms of your openness was not just about you - you're so sensitive to everything - you really were so much closer after that exchange - this is exactly what you want - you are beginning to be yourselves with each other and trust each other that who you are is who the other person loves.
And it's true - you do love who the other person really truly is, both of you. He truly, truly is into you in every way. This masturbation thing and the openness about it and the way this exchange went - you're fine with whatever he does as long as he takes care of you! - that's the crux of the whole relationship, right?!! - that is a good thing. Now he can share stuff about himself and not worry what you'll do.
He feels safe!!! This is so great. Please believe me - what you get when a man feels safe is soooooo much better than the control over his behavior you have to give up to get that feeling of safety. You'll begin to feel it too - and you guys are off to the races!
About the ickyness - just leftover stuff, just habit. Do what you've been doing, keep allowing, being, trusting, saying your feelings; let things roll and unfold. Just don't give energy to the icky stuff. Go in for a moment; feel it in your body, and then let it go through the beautiful garden of light and the love you really have between you.
The Gremlin will never, never go away forever. Just don't give energy to the Gremlin; keep expanding; keep being the sky and K and everything, and the Gremlin will get smaller and smaller in response, and you'll by annoyed by it less and less and live your life from a place of love and trust and better things to do with your thoughts than hand them over to the nasty Voice of the Gremlin!