Summary: You should have realized he'd written the rules in erasable ink.
Disclaimer: I don't own these characters, make no money from this, and promise to put them back when I'm done.
It's like being best friends with a jackhammer, most of the time. An automated jackhammer that runs on its own and needs no guiding hands to keep it at its ever-destructive task.
Other times, it's more like being friends with a wrecking ball or a five-year-old -- but in the end, you know you will always want him around, always.
You step off of the elevator and -- now that he has accepted your invitation into yet another of the dusty, disused, too-silent rooms of your life -- ask him if he thinks things will work out. The answer is a foregone conclusion: House says no.
Then he says it won't be your fault when it all goes wrong, and this, right here, is why you need him. Anyone else could tell you the same, but House is reality, a boulder when you'd hoped for a feather-bed, a glass full of vinegar when you'd only wanted a little wine. If you were to blame, he'd grab you by the metaphorical scruff and shove your nose into the metaphorical pile of shit and you'd know you had it coming.
He is therefore the only one whose proclamation of your innocence you will ever truly believe.
You'd lied, of course, when you said to House that there was no social contract between the two of you.
Or, not lied as such, because your meaning was understood: the two of you simply ignored all legal precedent and drafted an agreement of your own. Your rogue piece of paper has none of the standard clauses, yet it is absolutely binding.
That's why you are sitting with him at Mickey's Diner at eleven on a Wednesday night, acting as if you're irritated when he orders a second large strawberry shake (on your tab) and scowling mightily as he railroads several more of your fries into his gaping maw. The agreement between you explicitly forbids your thanking him for his companionship, his truth-telling, his whole just-being-Houseness that makes life bearable and not, in almost equal measures.
So you're buying him dinner and, according to the contract's stipulations, allowing him to pretend he cadged you into it. "Do you ever come up for air?" you say, and his flexing, fry-chewing smile is all the answer you get. In that moment you see that something has changed, that he knows how much you depend on him and why.
Maybe he always knew, and you were the one who had to figure it out, and now he knows that you have.
And House, it seems, is all right with that; he is happy about it, even.
It has come as something of a shock. Until now, you were certain your contract prevented so much self-revelation on your part, or his. Experimentally, you grab away the silver milkshake tumbler, still half-full because there was more shake than there was room in House's glass.
It tastes good, and House lets you keep what you've taken. He just keeps smiling and eating your fries.
He must have amended the agreement, you think, and not told you.