She had a child from a sperm donor and wanted to find out who it was, so when she found out she went looking for him with her son. She coincidentally saw him in a park while looking for him, and he saw his wife with him. My friend could tell, because they were wearing their rings. 

Then she approached the two looking mad and yelled at him putting on a whole scheme acting as if he was cheating on his wife with her! It was crazy! The wife didn't believe my friend, but when she brought up to take a DNA test to prove that the child was his, they did and when the child proved to be his, the wife and the husband ended up divorcing.... I suppose he forgot that he used to be a sperm donor, and he didn't end up paying child support, but it's just something crazy my ex-friend did....