Is this on PC or one of the consoles?
If PC, did you add any new mods (new to you, that is) at or near the time this started happening? Did you check to insure you've not fallen victim to the a-bomb? (Wrye Bash can detect and fix this for you.) Does Wrye Bash detect bloating with the corrupt saves? Posting your loard-order might help in case you run any known unstable mods (or mods that conflict with other mods).
Also, how do you save? Some save practices are more corruption-prone than others.
-Decrepit-