Answer:
Sorry to disappoint you but Raiden completely loses his mind. I'll give you some quick history. Sorry for the dates
2009 - Defeats Metal Gear: RAY with the help of Solid Snake and beats Solidus Snake as well.
Late 2009 - Gets with Rose.
2010/11ish - His and her child is conceived.
Late 2011 or early 2012 - So called miscarriage (child was born). Memories from the First Liberian Civil War as a child soldier start to resurface. He then begins to drink heavily and leaves Rose.
2012 or late 2013 to early 2014 - He undergoes the Cyborg Ninja program.
2014 - Liquid Ocelot's Insurrection