Angel could have cared less what was going on between Buffy and Spike at the moment, throwing a glaring look at Spike when he cursed at him. He was being sincere, but Spike never took it that way. He had tried to make peace ,at least for the moment, with the blonde vampire, but he was always throwing something back at him both literally and figuratively. He wanted to say something, but both Buffy and Willow being there prevented it. "I just promised Willow a very long time ago that I'd watch her back.." what he didn't say could have stung both of them far more than he wanted to right now and he turned his back on them both.
"You shouldn't get up, Willow. Just sit down for a moment." He stepped closer to her.