You and Estelle were dating with a while now. You were also an (alpha/beta) and she was an omega.

You started to notice that she would settle in one of the spare bedroom more often, bringing blankets and pillows.

You also noticed some of your clothes started to disappeared. One day you decided to enter the bedroom and saw a pile of clothes, pillows, plushies and blankets on the bed.

Estelle was in the middle of the pile, cuddling against a pillow. It finally clicked to you that she was nesting, a thing omegas usually do.