Why do they harass us

So my NOW ex has been cheating on me I found out last week. So I put him out. Everyday the home wrecker has been harassing me with fake pages sending me things and making fun that she STOLE my man. I really don’t care about the bs. He can be her problem now. But if you have him now why are you bothering me???? Like why do the side chick always harass the girlfriend or wife??? Like wtf is the beef with me. You knew about me... I didn’t know about you!!