When was the last time you changed your recoil spring? It looks like the guide rod is taking harsh punishment for it to crack in that spot most likely due to a weakened recoil spring. I’ve never had that issue on my Sig but I would recommend getting a new recoil spring/guide rod.
All guns have parts break with time. I’ve never seen a guide rod crack that way, but it could be related to a weak recoil spring. Keep it changed out every 5000rds or every 3-5 years depending on its use.
New recoil spring guide for P225 9mm is about $10. Parts kit for servicing is $20.
If it were my pistol, along with the guide rod I would replace
slide catch spring
decocking lever spring
trigger bar spring
recoil spring
inner and outer slide roll pins
These are all parts that come in a parts kit.
Along with proper lubrication, replacing the recoil spring and slide roll pins every 5,000 rounds is probably the best thing you can do to extend the life of your pistol.
So where’s the best place to order the kit? Found some on Sig’s site, but they do not list the “P6” as an available model… will the P225 parts kit work? Also, I don’t think it included the guide rod and I didn’t see them on there anywhere… any other ideas?