She usually spends her day off with her husband.
What does spend off mean?
her day off,not spend off
Ιt means that she is away from work,that she doesn't work οn that day,so she spends her free time with her husband.
check these examples:off,prep.,adv.- away from work or duty:
He’s had ten days off school. She’s off today. • I’ve got three days off next week. • How many days did you take off? • I need some time off.