i made a family and then one of the girls got married to the sekemoto kid and she moved in with him

so i wanted to play that family because her parents wanted a grandkid

when i went to play it she wasn't in the game

I have story progression on and i made sure i saved the game

because i have an external hardrive and it always falls out and my game crashes

With Story Progression on, she probably moved out of town or died. If you don't want Sims to move out/die/etc, turn SP off.

Or get a mod like Indie Stone which fixes Story Progressions "quirks"