Imagine that your OTP, after trying forever to have a baby (or adopt a baby) finally gets pregnant/certified to adopt. Now one day, about a month after the baby shows up, a freak accident happens. One half of your OTP is driving home baby supplies when a drunk driver slams into the side of the car and kills them. The other half of your OTP finds out after repeatedly calling their cellphone with no response. The remaining half now has to raise the child with a reminder that the child should've had two parents.
Authors note: sorry.......