Ajeet says: "She is the mother of my children's father."
Let's identify who "my children's father" is:
Ajeet's children's father = Ajeet himself
Now, the woman is described as "the mother of my children's father."
Since Ajeet is his children's father:
The woman = the mother of Ajeet
The woman = Ajeet's mother
The question asks how the man (Ajeet) is related to the woman.
If the woman is Ajeet's mother, then Ajeet is the woman's son.
Therefore, the answer is Option 3: Son.