Thinking of donated sperm is a long shot.
The woman in this scenario is living with a guy! He might have just donated her the sperm by a funnel....!?
Basically if a woman cannot find someone to marry her, then the need to have a child is good enough reason for let the man have a one (or more) nights of fun with the desperate woman.
Both happy?
Nope!
Well, they both get what they want. so, happy. Yes.