An Unexpected Advirsary

This tells about how one of my enemies came from where I least expected.Please Rate/review

If I had known, If only I had known,
That when I came back we would no longer be friends,
But enemies as though sworn by oath.

He came between us upon his return,
And was it Jealousy that drove you away?
Why can't it be like it was?
without the pain

Now he is by my side,
And you left for more than me
for stuff like popularity
I hope you see this so you will know,

I went the right way,

Which way did you go?