"I want to know who you're having the affair with"

Is it just me or does House cross the line a bit in Sex Kills with his assumption that Wilson is having an affair based on a box of chocolates, his reaction to that assumption, and his lack of support for his friend?

[Wilson is buying a box of chocolates from the little shop in the hospital lobby]
House: Who's the lucky woman?
Wilson: My wife.
House: No, I don't want to know who gets the chocolates; I want to know who you're having the affair with.
Wilson: [to the sales assistant] Fell on his head as a child, tragic.
House: Norwegian chocolate. Frankly, you buy that stuff the terrorists win.
Wilson: Some people bottle up their feelings; have them come out as physical pain. Healthy human beings express feelings such as affection by giving gifts.
House: Gifts express guilt. The more expensive the expression, the deeper the guilt. That's a $12 box so that means you haven't slept with her yet, or she wasn't that good.
Wilson: It's not all about sex, House.
House: Really? When did that change?
[Wilson glares at House]

~

House: Wilson! How long can you go without sex?
Wilson: How long can you go without annoying people?
House: No seriously, a week? A month?
Wilson: I'm not having an affair.
House: I didn't say you were. Not in this conversation.

~

Wilson: You sure you're right?
House: Absolutely. Your socks don't match, which means you got dressed in the dark, which means you didn't want to wake your wife which means you didn't want to talk to her, which means…
Wilson: I was referring to your patient.

If Wilson had been having an affair then you'd think House could have been a bit more supportive - harassing Wilson and asking him how long he can go without sex is hardly likely to persuade him to open up about his personal life! And Wilson was there for House through the whole Stacey thing - picking up the pieces the first time she left him and offering advice but still letting him make his own decision the second time. Admittedly afterwards he did tell him he'd made the wrong choice, and was quite happy to shout at him and at Stacey when he thought they were being stupid, but he never made fun of House or belittled his feelings.

Perhaps it isn't such a jump that House would think Wilson was looking elsewhere for female company: we know he's had at least one affair and two failed marriages, and that he works long anti-social hours. But we also know he makes friends easily, has a lot of female friends (Stacey and Cuddy among them) and is someone that women feel comfortable around and telling their problems too (like the crying nurse in Need to Know, or the new oncology nurse in Fidelity).

This isn't the first time we've heard about problems in Wilson's marriage though. In Babies & Bathwater he makes it quite clear to House - and to us - that he's having problems at home:

Wilson: "I've got no kids, my marriage sucks. I've only got two things that work for me; this job and this stupid, screwed-up friendship, and neither mattered enough to you to give one lousy speech."
House: "They mattered. If I could do it all again..."
Wilson: "You'd do the same thing. Well, you'll be gone soon, too."

In Sex Kills we hear that maybe House is part of the reason things aren't working out:

[House and Wilson are playing foosball]
House: "Are you going to tell her?"
Wilson: "That you suspect an affair? Sure. She already hates you, why not? [...] There's nothing to tell."
House: "Why are you playing foosball here at 8 o'clock at night?"
[House's pager starts beeping]
Wilson: "You always want to simplify everything. Boil it down to nice, easy equations; nice, easy answers."
House: [starts walking off] "Go home and have sex with your wife."

So we get Wilson trying to tell House that it's not a simple problem, House having no sympathy and prescribing sex as a cure, and Wilson saying that Julie hates House - is she jealous of the amount of time Wilson spends with him, or does she just not like him? Let's face it, on first impressions House is definitely not likable!

Actually, the fact that Wilson is playing foosball with House at 8pm should have told him that there was no affair - if he had another woman to go to, wouldn't he be spending time with her rather than with House?

In Damned if you Do we get the first sign that Wilson has problems at home:

Wilson: You want to come over for Christmas dinner?

House: You’re Jewish.

Wilson: Hanukkah dinner. What do you care? It’s food, it’s people.

House: No thanks.

Wilson: Maybe I’ll come to your place.

House: Your wife doesn’t mind being alone at Christmas?

Wilson: I’m a doctor, she’s used to being alone. [House raises his eyebrows] I don’t want to talk about it.

House: Neither do I.

Actually that brings us on to something else. Wilson doesn't want to talk maybe because he doesn't know how to, or doesn't know what to say. But House isn't the sort of person who likes to talk about anything personal unless it's just for his own knowledge and satisfaction:

House: Your shirt is ironed. That means you haven't told your wife anything.
Wilson: Let's say you're right.
House: You're saying I'm right?
Wilson: No. Let us say. Does it occur to you that maybe there's some deeper guidance than ‘keep your mouth shut’? That maybe a friend might value concern over glibness? That maybe... maybe I'm going through something that I need to have an actual conversation about?
[Beat. House’s pager goes off – he checks it]
House: Does it occur to you that if you need that kind of a friend, that you may have made some deeper errors?

Still, despite the lack of sympathy, he goes to House when he needs somewhere to stay - not to a hotel (which a doctor in his position could easily afford) or to any other friend.

[House opens the door to Wilson standing there wearing a shirt, scarf and overcoat with a packed suitcase next to him]
Wilson: Could I stay with you for a few days?
House: You idiot. You told her.
Wilson: She told me. [House is stunned into silence] Things have been crappy at home lately; I figured I wasn't spending enough time with her. I figured... Turns out you're right, it's always about sex. She's been having an affair.
[They stare at each other for a few seconds then House moves back to let Wilson in]
House: Want a beer?

So even if House isn't the supportive, advice-giving friend that Wilson is, at least he'll lend him his sofa...