Basically I think Puck lived with Kurt after his mum left/died. They were still in highshool but they were like this perfect domestic couple raising a child (or two) None of the glee club knew they were a couple except Finn, I remember there was a scene where glee club found out after Puck brought in sarah? after there was no-one to baby sit.
Like I say I might have mashed a few stories together or dreamt this up but if it sounds familiar to anyone please let me know. Mods sorry if i've tagged this wrong i'm a bit of a LJ fail.