Is my marriage still valid if my husband doesnt pay mehr before due date?

Salam alaykum, Is my marriage contract still valid if my husband doesnt pay the mehr? 1st he told me to make it affordable for him so i lowered my mehr to $1000. When the imam asked me when the mehr would be paid my husband answered before i could. And it is due in roughly less than a month. If he has not paid the mehr by said date is our marriage contract still valid? I cant find an answer anywhere. And nothing i find seems to relate to my situation.