Dear heart, no partner has anything that is worth signing a legally binding contract WITHOUT the benefits of marriage that will leave you holding the proverbial bag.
Long-distance relationships are very deceptive in nature because each time the people see one another, there is a certain sense of urgency and romance that is beyond what is "normal" or even healthy.
As people spend more and more time together, they begin to notice attributes, habits, and behaviors that they were simply unaware of. In my own situation, I had moved far away from everything that was familiar to me to an area where it was very difficult to find employment, and I honestly believed that I could not leave when I began to notice that my future spouse was sending up some red flags - I didn't believe that I could make it on my own, by that point.
Run.....don't walk.....away from this man. Make your decisions based upon common sense and YOUR needs and requirements rather than buying into the false dynamics of the "long-distance-passion" that will inevitably fizzle out as soon as you put your signature on that document.
His issues are HIS issues, and, unless you have spoken directly with his ex, you really don't know what truly happened between them. There is his story, and there's her story. The truth is somewhere in between.