He is a believer, even if his lifestyle and behaviour does not show it. Although he recognizes his own failings, he hopes God will see he is a good person and will forgive him. Many JWs that are the worst examples, are often the most critical on how others live their lives.
A JW relationship with a 'wordly' person, will often make the wordly person susceptible to influence and conversion to become a JW as a condition to saving the relationship. He might feel that in converting you to become a JW, would offset much of his bad behaviour. It would not be surprising that if you started studying to become a JW, he will become very devout, maybe even fanatical.
Congratulations on undertaking your own research and for not blindly thinking that your relationship will workout and be the uncommon exception.