As a widow of 4 years, that has been suggested to me several times. Not quite ready yet, but when and if, then my brother, a licensed PI with a security firm, would check the guy out and do a through job of it.
Think of doing an online check on him, there are many companies online that don't cost that much. You'd be shocked at how much you can find out about anyone at all. One of my friends used that to check out a new date, showed me the print out. I'd be horrified to have that much discovered about ME, but it's clearly possible.
Otherwise, good luck. There ARE nice men out there, finding them is the next thing.