Well look at it this way...
If your actions are so powerful that you could cause two other people to break-up, then you would also have enough power to cause them to not break-up and get back together.
Can you do anything which would cause them to not break-up and get back together?
If you can not, then you also would not have been able to do anything to cause their break-up!
Therefore you are not to blame!
In reality, if two people truly want to be together, anyone trying to break-up their relationship intentionally or otherwise will only cause them to grow closer together. Right?
As for why you feel so upset, maybe it is just what I call "earthquake syndrome". I was in California once and went through my first earthquake. It really rattled my nerves! I mean REALLY!
And after a bit of asking around, someone explained to me that we rely on the earth as something stable and always there. When it suddenly moves, it makes one think there is nothing stable to rely on anymore.
Maybe your Aunt and Uncle are your "earth"? And that is now moving?
Here are some tips for dealing with "earthquakes". Maybe that will help you as well?
http://www.cyf.govt.nz/documents/abo...earthquake.pdf