consequences of overwatering

Bad news. I just can't seem to figure out how to water the Frithia humilis I have. :( And the plant doesn't give me any chance to.
At first there were 3 growing points and after a while, seeing how soft and limp it was, I've decided to water. The pot that normally dries out after two days stayed wet for a week (the plant didn't drink anything) resulting in one growing point rotting off. And the rest didn't get any firmer. New leaves and flower buds came up like nothing happened (ca. 3 weeks past) and there was a lot of sun lately. I water again. Another growing point is gone in a day! Now since the substrate just doesn't dry I've put the rest of the plant in an even smaller pot with dry pumice. Now what? The worst thing is I still don't know how to properly water it, even if the rest survives (I think, I'm just not watering it ever again..). Any ideas what I should or shouldn't do next?
Well, at least the only left flower opened today and it's so tiny and cute!
Thanks for your comment