family plan changes without losing unlimited

My husband and I are on a family plan. He has grandfathered in unlimited data and we are not willing to lose this. I am just curious if I can change my stuff without altering his because I do not want to seperate as I like the joint plan but our bill is high and just seems to keep getting higher.

I do not have the grandfathered in unlimited but my husband does and is not willing to lose it because he will not be able to get it back.