Before you can solve anything you need to separate and clearly distinguish the issues that you have to resolve before coming to any conclusion.
As far as I can see, there are two separate issues that are blurring together in your mind which are contributing to your confusion.
The first issue that seems the most predominant in your mind is the question of rekindling the love you had with Leo.
The second issue that you have is wondering whether the religion you are in is the truth.
At this moment in time the second issue is the most important to resolve, due to the fact that it has a huge bearing on the first issue.
If the Jehovah's Witness religion is true, the answer to the first issue is obvious. You stay with the chap you're with and you learn to love him and progress in the relationship with Jehovah's protection. All very nice, but not exactly what your heart longs for.
If the Jehovah's Witness religion is untrue, the first issue becomes a lot more complicated.
The problem now is remaining objective in your examination of the Jehovah's Witnesses and your faith.
The question for me is, would you even be considering the credentials of the religion if it wasn't for the fact that your heart's desire lies outside of the Watchtower? If Leo had been a Brother and everything was authentic and up to the requirements of the religion, would you at this moment be questioning the truthfulness of the religion?
Regardless of the answers to the question of your motive, there remains the very important point of whether the Watchtower is the true religion or not. You also need to know if there is a god or if there isn't a god, if the Bible is true, or is it a myth like any other 'Holy Book'.
It is only when you know the answer to those questions that you will be in a position to make a wise long-term decision.
Just to finish... I knew a JW sister who remaind in a loveless marriage all her life, staying with her unbelieving husband because she was loyal to the Watchtower, only to reach the end of her life and find out the what she believed all those years wasn't the truth.
I can't imagine what she went through when she was in hospital, after having suffered a stroke, and was lying there thinking about her life and what had passed her by.
You have some very tough decisions to make that don't just affect you. Your belief system is at the very heart of your decision making. That is your starting point.
Good luck in your decision making.