This whole relationship-by-web thingee (to use the technical term) has its benefits and drawbacks, and one of the latter is not really knowing whom you're speaking with. In my day (he said, mouthing his gums, which tasted like tutty fruity) we met people through social events, acquaintances, red light districts and the like. There was less that a person in reallife could "stage manage" to make themselves semm wonderful than they can on the Internet.
So maybe you could consider meeting this person in a public place for lunch, or dinner. Try it a few times, always in public. See if his facade cracks, and find out what lies within. Ask him a lot of questions, and find at least a few you can check on. Machiavellian? Sure! [img]smile.gif[/img] But if you want to know what he's like, these are time-tested methods.
Well, these and marrying the guy, but divorces are messy and time-consuming. Try the other methods, first.