See "These Things Just Seem to Happen #3" (in Sims 2 Photo-sharing) to know what gives here.
* * * These Things Just Seem to Happen #3 * * * https://www.boolprop.net/viewtopic.php?f=74&t=5357
For photos of the couples in question go to the original family scrapbook here: https://www.boolprop.net/viewtopic.php?f=74&t=2613
I should be along with the answer in These Things Just Seem to Happen #4- I kind of doubt I'll run out of material.