I have been living with my boyfriend for 4 years with our 2 year old son. And he is telling me I have to leave. Because I'm not on the lease.

Then you have to leave, but he has to go through a legal eviction process. He can't just kick you out. Even though you are not on the lease, you still have established residency. Therefore, you are considered a month to month tenant. Depending on where you live (ANY question on law needs to include your general locale as laws vary by area). He has to give you notice between 15 days and one calendar month to vacate. If you do not leave by that deadline, then he has to file for an eviction order.

If he locks you put or tries to force you to leave, that would be an illegal eviction and you can sue him. If he changes the locks while you are out call the police, show them ID that indicates you live there and they will force him to let you back in. If he tries to get physical, call the cops and ask for a Restraining order that will force him out of the apartment.

If he gives you legal notice, then you go down to family court and file for child support.

By the way, there is no such thing as squatters rights in this case.

He may or may not be using the lease to hide his real motives. What does the lease say about the number of persons allowed? Has the landlord been raising this as an issue? Has your relationship deteriorated? He can ask you to leave but to force you will require eviction, which takes some time but you will be out eventually.

But yes, first there is really no such thing as squatters rights, and certainly not for a renter.

You have to leave and move if he tells you, if you don't, he will have to go though court to evict you though the courts.