As long as he is fully content with his sex life (he says he loves you and that he wants you 'so bad' - maybe he just enjoys prolonging the sex - which is great in my opinion) then I do not think there is any reason for concern, unless you are trying to conceive at the moment. Sex is about a lot more than just penetration and if it's really great sex then whether one finishes off at the end or not is not really a big deal, in my opinion. Have you considered finishing him off orally or manually, after penetration - maybe it could help? But again, unless he is discontent with it, I would not stress over the issue.