I'm not sure what the original inspiration for this song was (apart from being in a relationship myself) but I'm getting the feeling it had something to do with someone who undergoes a lot of torment and punishment in their life... Maybe even sacrificing themselves for love.
And I guess the mention of a prison could be interpreted as literal as well as metaphorical, thus referring to a prisoner.
The title itself was actually inspired by the American Dragon Jake Long episode "Half Baked"
Jake: But what about you?
Rose: You can't save me Jake, it's too dangerous.
Jake: You're worth it.