I told him I wanted to end it and he refused. He wants to keep seeing me and spending time together. He texts me all day and we see each other once a week.
This line is particularly troubling for me because it along with the other information tells me volumes about this man's character. In short he's selfish, he cares far more about his own feelings than yours. Additionally, he is coward that will not stand up for whatever it is truly believes in and that is why he won't openly enter a "relationship" with you right now.
Jehovah's Witnesses aren't supposed to date people who are not Jehovah's Witnesses, but if he's with you secretly and having sex with you, then he obviously doesn't care about violating those "moral" standards privately, only publicly when he would have consequences to face. That, in and of itself, is a dangerous mentality, it's the same one used by abusive mates who like to put on a front that everything at home is perfectly alright. If a man only puts on his moral standards when other people are around, then what's going to happen when he stops putting them on for you too?
The reason he asked you to "start meeting with his mom and another female JW to discuss the contents of the book" is because he wants them to convert you to his religion so that things will be less difficult on him, not because he cares about you. It's most definitely not because he thinks it's such great religion because if he did, not only would he be teaching you about it himself, but he also wouldn't be blatantly disregarding its rules.
My advice to you is to leave this relationship and find someone who wants to be with you as you are without having to change something so fundamental about yourself first, and someone who can be with you honestly and openly without fearing what other people will say or do.
It's your choice of course, that is just what I believe to be the wisest course of action, and I could be wrong about him, but I would exercise caution if I were you.
EDIT: Additionally, another option is open to you, you could try and get him away from this religion that he clearly doesn't want to be a part of deep down, because if I had to guess most of the emotional and commitment issues he has are probably stemming from that situation continuing, in any case it would be far better for both of you than you also getting sucked into the Orwellian night mare that is the JW religion.