I can't vouch for whether or not that is what he was saying, but if so, it's pretty likely to be true. People with families, right or wrong, tend to place the security of their family's future above their own political beliefs.

Snowden's actions were brave, regardless of his family status, and I don't wish to downplay that even one iota, but yes, if he had a wife and three kids, it likely would have made his actions even more of a longshot.