What does 我三谁了 mean in 我也不知道，我刷四绝朋友告诉我有人刷喇叭骂我小三，我不知道我怎么就小三了，我三谁了? Could anyone explain to what 我三谁了 mean in

我也不知道，我刷四绝朋友告诉我有人刷喇叭骂我小三，我不知道我怎么就小三了，我三谁了?!

I know that the whole sentence more or less means &quot;I don’t know, my best friend told me that someone used the world speaker to scold me as a mistress, to scold me as a mistress, .......?!
What does 我三谁了 exactly mean?
It seems to be a very easy to understand sentence but I just cannot understand the 三 there.  If I'm I'm taking a guess I would say that it's &quot;Who is the third?&quot; but if it's that then I have a hard time understanding it inside the sentence.
This sentence is not grammatically correct, and will not be understood without context. However, with the full context, I think most natives would be able to understand it.
Here it means &quot;to whom I became a mistress?&quot;