I JUST REVIEWED RIDE TO HELL SO IM STILL CALMING DOWN so the ending while horrible actually makes sense just reverse everything. So instead of your army dying they survive and win and the relays don't blow up the reapers are Defeated. There is ending DLC but I hope this helped.
Infinite Missile - Multiplayer Platinum Runs Made Easy
To get this glitch to work there are a few items needed and a preferred character (even though it can be done temporarily with all characters). N7 destroyer soldier (spec'd with devastator mode maxed along max ammo build) Main weapon m37 falcon or striker assault rifle or any rifle that shoots grenade rounds and equip any second hand weapon as well. This glitch only works with a full group of 4 players reliably any less and the glitch tends to stop working from time to time, this glitch can also only be done by the second and third people to join the party. Now at the start of the match you need to switch to your missiles and fire off all but the last shot, then shoot off the last round and hold down the trigger until you hear the missile launcher clicking, while its making the clicking noises switch to your primary weapon while still holding the trigger down if the glitch worked you will now have infinite missiles, its best use devastator mode to reload as well you only have to turn the ability on and off to reload.