My boyfriend wants to be car...?

Hi all. Basically, my boyfriend wants to be a car.
It started last year a couple of weeks into our relationship, when I went to his house for the first time and i noticed that the ceiling above his bed was plastered with cutouts of cars from magazines. I didn't think too much of it at first, as he had told me he was a car enthusiast. But then his behaviour started to get really erratic.
I noticed his IM name was 'HoneyHonda,' at one point, and his avatar was, lo and behold, a Honda Civic. 'Typical boy behaviour,' I thought. Then on his Facebook page he had 60+ picture albums of f****** hondas, and his status' were mostly car related, especially when he was drunk, saying things like 'Taking myself out for a spin later' and 'Gotta change my oil at some point.'
Then, one day, when he answered the door to me, he was wearing a Magic Tree air freshened on a chain round his neck. He says he wants to get a goddamn lower back tattoo of an engine. So basically a tramp stamp.
Its even spilt into our sex life- one time he moaned 'I've just backfired.' I started crying to myself when I went out for a cigarette afterwards because I felt like I was in a relationship with a vehicle. I don't even know if this is a fetish or some kind of psychological dispute with himself. Am I being too harsh???