I had a perspective that might help explain his tortoiseyness in relation to how slowly he seems to be developing a sexual bond with you as opposed to how quickly he seems to have developed it with the other GF. Some men need to build a concept, for lack of a better word, of sexuality around their partners in that they feel more comfortable knowing what turns her on, or off, what sends her through the roof, and what just doesn't matter to her. For some it helps to have some tension and expectation going into a sexual situation. Also, if he is a "giver", he likely wouldn't be as interested in a one-sided exchange if you were unable to benefit mutually from it at the time. It may be that the door feels only partially open to him after a long period where sexual contact was off the table, and he may just need to start to "feel" you more in that sense. For the other GF, that door may have been open at an earlier point allowing him to have that buildup earlier. After realizing how much you were hurt it he may be putting a lot of pressure on himself making it difficult for him to just be natural with you until he feels like that tension has passed.
At any rate, he sounds like he does care about you and that is the most important thing. Perhaps if the two of you could establish a more comfortable rapport in regard to sex it might help him relax a bit.
As a side note: I don't know where you two are with expectations of sex, or how much time you have spent discussing it in a suggestive as opposed to factual matter, and I don't mean to suggest. A lack of that kind of interaction. I hope the best for the two of you