You have a current tenant who signed a lease renewal. Yes, you can hold her to the lease renewal. If your lease has a lease-break clause, you can enforce that, or you if none you can do as the law allows and re-lease the unit as quickly as possible, charging the breaching tenant for the lost rents. Yes, you are damaged by her change of mind--you could have been marketing the unit for rent for April 1 had you not received her signed lease renewal. Now you will likely have an some unpaid rent while you market the unit to a new tenant. Most LLs on this forum are quick to tell you, don't let your tenant's relationship problems become your problems. Shack-ups have just as much responsibilty to follow through on their contractural obligations as anyone else, even though you might have been forewarned that they would not take that responsibility any more seriously than they did the commitment to each other. It's all just for fun, right?