I really can't see what the hell his problem is. He has plenty of money, he only fights what? twice a year? According to all reports his father's health is fine and he isn't married - don't even think he has a GF - and has no family or the possible problems that come along with one. What can be so stressful about his life? Manny Pacquaio fights in much bigger fights than GSP, does a lot of promotion, he's married and has a family AND he's a congressman in the Philippines. Most top level fighters are married and have kids, whether MMA or boxers. I can only think of one thing that may be the cause of such stress in his life, and I'm sure some people will get a little pissed off at the suggestion...maybe it's time to come out of the closet?
Whatever the case, I wish him luck in the future but I'm pretty sure he'll have few problems down the line.