Just listned to this and seems like there was going to be happy ending i assume it was cut because it would kinda suck if he talked about all that and then game ends sadly.
Leaked script, I think, noted that the mass relays could of been saved and have shepard living still.
Can't remember all the details, and I could be completely wrong.
Don't think that means there was a happy ending, it was probaly to make the ending more of a tear jerker when you realise that can't happen. But it was probaly too long and so cut up.