Pregnancy (by illegitimate partner)

This character gets pregnant with someone who isn't their legitimate partner (such as their husband or boyfriend).

Pregnancy is either the product of an Infidelity (or of Swinging) or something the couple wants because of an infertility of the husband/boyfriend.

Pregnancy following a "Wife Swapping" is included in this definition, whether the pregnancy is desired and/or approved by the husband or not.