I certainly understand your frustration. While this is an unfortunate (and unavoidable) side effect of the scale of changes that get made during the beta testing process, we are going to start being more transparent regarding when we estimate new patches to come out. Hopefully this will give a fair warning so games can be completed before the new update, etc.
Also, as some users have suggested, disabling auto-updates for the game in Steam can help avoid getting a save game nullified before you're done with it. (Please use this sparingly though, as the updates have important fixes and improvements).
FYI, we estimate the a new patch will go live Tuesday April 24th. We can't be 100% certain of this date until internal testing is complete.
Sorry for the inconvenience!