Is there a legal limit to how many days my children can visit since?
There should not be however in most leases it asks you to list the occupants etc. did you explain you had partial custody of your children who would be coming and staying at times? Even if not, you are not housing a bunch of people for free that you left off the lease, they are your kids. Do you rent from a private owner or live in an apartment building and what state do you live in? All leases are differed but this should not be a problem unless maybe they are there 24/7, 365, in that case just give the landlord heads up on the children. It could concern them depending on the space of the place if it's an apartment or very small house and how many kids there are etc.