My husband and I have a problem with a house that is owned only by my husband. The problem is that his ex-wife resides in the home with his 2 teen age children. They pay no rent and have no lease. My husband now wants to sell the house and the new owner wants the ex to sign a lease. She will not sign the lease. She is hoping that this will stall the proceddings with selling the house. She was told in November that the house was being sold. Will my husband now have to evict her from the residence or will the new owner?

What did the divorce agreement say about the house?

If the buyer is willing to buy it with her still living there let him. She might take it more seriously if the new owner gives her a pay or quit notice.
Your husband might even offer to reimburse him for the expenses in evicting her.

Yes, does the "ex" have any claim to the home by being on the deed or by court order in divorce court.

If she has no claim to it at all, just give her notice and evict her.