Orion526,
I bought the P228 second hand two years ago. SInce then I have put way over 2000+ rounds thru it myself, who knows how many were fired before that. If you take off your grips you will see a 3/4 circular wire/spring towards the top. This is what broke. It holds up the lever that attaches the trigger to the hammer. I have had the pistols grips off a few times and this wire tends to catch on things, this I believe was the main cause of its fatigue.
When I called SigSauer(603-772-2302) they told me it was reccommended that this wire/spring get replaced every 3 years, regardless of how many rounds fired thru it. Like I said earlier, they sent me the spring for free!! Give them a call and maybe they can send on out to you, just in case you ever need it. It really is simple to put in, just hook one side into a hole and slide the other end into a grove. If you take your grips off and look at the one installed now you will understand how it works.
I will reiterate: I believe the springs breakage was more the result of my actions than anything else.
Sgtar15