People are saying she killed herself for The Doctor, she didn't. She killed herself to give another version of herself a better life.
I do agree but she was at the same time saving the doctor so even if it wasn't a completely conscious (she was having dreams about him Rose said) decision about the doctor it did have roots and I think it would it was something she did for him. I really have no idea why I'm going on so much about it because I really don't think I buy it. I mean Rose looked into the time vortex for him, went missing from her family for a year, her family got in lots of danger and she ended up trapped in an alternate universe which she then broke through. Martha had her entire family pretty much tortured for a year. I don't know...I really hope its something totally unexpected.