It is different for everyone I am sure, but I would have never made it through without the strong support of my family and personal pitching coach. Some guys have strong girlfriends, others have agents and others have strong coaching staffs behind them. I think that all of the dynamics can work, but they all have pitfalls. Agents are only interested in players with big league futures and their support wavers when your numbers go down. Family is strong, but sometimes you need to hear positive talk from someone other than your mom or dad.
Girlfriends can be pillars of support, but also be the most dangerous.
Players have to find girls who know the difference between the subtle and mysterious behavior that leads to intrigue and wonder in a relationship and the girls who are completely self-centered and rude for the sake of being rude. The ins and outs of a relationship wreak havoc on players or send them to new levels of success or both. In my short introduction into professional baseball last year, I saw the fully actualized entourage alive and breathing with some of the best players in the game. You can tell what kind of player you are by the number of people who watch you throw a bullpen. Based on that little piece of wisdom, Randy Johnson and Todd Stottlemyre are two of the best pitchers in baseball.