Why is it that every time someone posts about this issue, at least one person has to chime in with the "get rid of the cat"?
Listen up- when a person takes an animal into their home as a pet, they are making a pact that they will take care of that animal, not just dump that animal if things get rough. A great deal of the time, when a cat is doing this, there is an underlying medical issue which should be cleared up. Often times, people are not providing something that the animal needs, such as access to enough litter boxes, or CLEAN litter boxes, or attention even. If the marking is emotional, change will trigger these issues, but small corrections, medication and/or pheremone therapies are successful.
Every pet owner is aware of the option that they can take their pet, this animal which is PART OF THEIR FAMILY, TO WHICH THEY MADE A TACIT PROMISE TO TAKE CARE OF, to a shelter, or dump it on someone else or the street, or to the vet to be "euthanizied". We all know about that. Some people are asking for options which are different from going immediately to what should be the last, worst case, option.
So please, be constructive and helpful.