This can go two ways, it will get really nasty, or he will let you stay. If I was a landlord and found one of my tenants was lying to me the last three years I would be pretty pissed. Now if your landlord has a legal standing to fine you then your are stuck paying it. Best you can do is try and talk him down a bit and have him turn it into a deposit so you can keep your pets and stay in your home. If you are a good tenant he WILL work with you. If he has no legal standpoint to fine you then that will be up to you to pay or not. If you don't then he will surely not renew your lease and you will have to move and figure out another place that will take those type of pets with a deposit. Ya that is messed up but you put yourself in this situation by hiding your pets. But if you have been an outstanding tenant the last 3 years he will no doubt work with you.