Overvaluing oneself is not specific to either sex. You may think reciprocity is “overvaluing”. I do not. I’d say its more like equality.
How does reciprocity apply here? My point is that fussy, nit-picking males aren’t worth the trouble. Single mothers have quite enough to do without adding a demanding being to the mix. Couple that with the complaining addition’s desire to expropriate her resources for his personal use, and you have an undesirable situation. I’m certain we can agree that any single person of substance is a target for users. Anyone who is raising offspring doesn’t need another dependent.