3 so far (I think), plus two nights ago I went out for an overnighter with the dog in tow, but despite making him a nice shelter with his favourite blanket and so forth, he wimped out and made a nusiance of himself until I gave it up just after midnight and went home. I think he's showing his age. I ended up sleeping in a sleeping bag on the living room floor, rather than wake SWMBO, as she had slept poorly the night before.
Shame, because I had gone with my lighter sleeping bag (first use) and minimal kit - just a bivi bag and no tarp. There was a full moon, I was toasty warm, and really comfortable... and the dog kept coming over and pawing at my face and whining.
Next time he stays behind.