Generally flirtatious could work because it's like "I'm not like this with you; I'm like this with everyone!"
But you'd sort of have to be generally flirtatious to begin with for it to be genuine, I'd think. Unless it was a 180 you wanted to stick with!
Okay, I'm going to try to be Great (ha ha!) and say that if you can flirt with solid boundaries, it might work. What does that mean? Maybe a quick sparkling smile initially while continuing to keep visits short and clipped. Later, at the right time, a small joke with a wink and then shuffle him out the door!
I'm totally guessing.
It could still be construed as manipulative because I guess technically it is. . . sort of. . . but if that's what he was wanting from you, he wouldn't see it that way.
All of that said, I think your WH is responding well to how you've been for the past few weeks so I would keep that up until it wasn't working anymore!
