In answer to the partner happiness thing, I think my answer is probably a combination of LaMer's and cherrylips. At first, DH was fine with it because it meant more sleep for everyone and DS was small so didn't take up loads of space. Then as DS got bigger and kicked more, DH started muttering about putting him in his own cot; to be honest, I might have considered that a viable option if DH had offered to help out at night in any meaningful way, but he sleeps like the dead and if DS were to need resettling it would be all me. So, if I am going the nights, as we've agreed (and I get a lie-in on the weekend to make up for lost sleep, if any, though DS and I sleep very well at night together now), then I am going to choose the sleeping arrangement, which I have.
It did cause some problems for a little while, insofar as DH was not feeling much intimacy from me and co-sleeping became the poster-child for those issues (it contributed, sure, but it wasn't the sole cause iyswim). I held my ground about maintaining the current arrangement and just tried to get more into physical intimacy (breastfeeding really slowed my sex drive, but I made an effort and it paid off because DH started feeling closer to my physically, and, in his very male way, emotionally).
Now DH is more amenable. Some nights he'll fall asleep on the couch in front of History Channel anyway, so if DS wasn't with me I'd be alone on our very big bed. And DH loves giving our now 19 month old DS a good cuddle/wrestle in the morning when he's still warm and mooshy.
Speaking of big beds, that's what we did to solve the problem of kicky-six-month-old. Instead of banishing him from our double bed, we got a super-king. It's luxurious and enormous and oh-so-sleep-enducing for all three of us.