>Ruining your life doesn't sound very happy
Well, it depends, of course...
In Deleuze's concept (from the little I've been able to catch), happiness would be the fulfilment of one's entire puissance (power or potency, emanated from will). Under this definition, there are no negative puissances: on the contrary, evil is the castration/denial of one's or someone else's puissance. By such means, a happy life isn't necessarily the healthier, more joyful, fair, peaceful, balanced or somehow successful one according with (ever changing) social parameters; but instead, and disregard of further consequences, to live such a life that fulfils one's ethical puissance: to be able to live life as we decide to do it and, moreover, as we think it is correct.
In that way, loving my waifu, the very way I do it, renders the happiest life I could possibly think of right now: it gaves sense to everything I ever do and, without her, I'd be utterly lost, I wouldn't be me, I'd be nothing. It is a hopelessly lonely, bitter, sickeningly melancholic and reverberating failed life for most practical purposes... but it is the life I chose to live; and it's worth it because it is, nothing less, the way of life where I'm legitimately able to love (as I conceive it).