Milky Oil

[prstack7]

I have been reading and troubleshooting. Here is what I have done so far:
1. Changed the oil 5x. It now looks clear.
2. Pressure tested the manifold. It passed.
3. Pressure tested the block. It passed.
4. Removed the manifold and valve cover. Everything looks good. The valve cover gasket came apart on removal, so it's possible that was a source of infiltration.
5. Examined externally the water pump. I don't see any evidence of leaking seals.

Upon reflection, I wonder if an episode this summer where I sprayed water around the engine compartment (it was not intentional, but I don't want to talk about it ) caused this problem. I had milky oil 2 years ago, but that cleared up after changing the oil 3x. Any ideas?

Side note: should I use gasket sealant when putting the new gasket on the valve cover?