Milk paint dilema

I'm about to put a finish on my kitchen cabinetry.

It is a 150 years old house and I built pine reproduction cabinets.  I intend to put milk paint on them but i've never used the stuff before. I've tried two different colors to figure out how to work with the milk paint. The first color(Fort York red, from Homestead)  looks good and dries nice. But it never seems to cure. A wet rag will always strip it without any effort, even after several days of application. Using any kind of water based top coat will dissolve the paint that will crack and look awfull. The brush will even put some dissolved paint in the varnish container. Two coats of well cured tung oil won't prevent the paint from massively adhering to a wet rag used to simulate a normal cleaning of the cabinet front. Wax did not seem to ad ANY degree of protection (the smallest drop of water will instantly discolor the piece) The only thing that seems effective is an oil based varnish.

I've read that milk paint is very durable, that you can put any finish on it as a top coat, that oil will make it age butifully, aquiring a unique patina, and so on. This does not seem to be true with the paint I use!

I just started some more test with my second color, and it seems to react differently. Have not tried it yet, bu I would guess it cures better. One thing: the red bag of paint has been open for some time (like several years). Can it be outdated in some way?

What is wrong with my paint (or me!)?

I guess my real question is: what would you top milk paint with for use on kitchen cabinets and get this aging antique patina while still having a moderate amount of protection?

Thank you.

Fred