Scorpio males are very passionate, though slow to reveal their inner feelings for fear of being hurt. They can have quick tempers, but these also hide behind the mask they put up towards the world. He enjoys mysteries and has high standards. They do, however, tend to draw women to them with a great magnetism, and are very sexual creatures.
Scorpio and Leo are actually a reasonable match, barring any serious jealousy issues. Scorpios, especially the males, can get jealous easily, and the Leo's need for admiration can cause him to become upset if she seeks it from others. As long as both parties are willing to make an effort and work to find a middle ground, it can be a very rewarding relationship.
As to your situation, I'll say this: a man who is willing to leave/cheat on his wife for you is almost never a man worth pursuing. The old adage "once a cheater, always a cheater" comes through in a lot of such situations. Do you want to be with a man who would cheat on his wife? Do you want to later possibly marry a man who cheats on his wife? And do you want to be with a man who randomly disappears for long periods of time and doesn't attempt to contact you? I think you can do better. Scorpios are mysterious and extremely attractive, and you're feeling his pull. But this one doesn't sound like the best match for you, in my opinion.