When not married couple splits up who gets to keep what?

Check out "Parental Rights"in your state. In my state I went through a divorce, however some people I know that were not married went through a court proceeding and custody, child support, etc. are determined similar to a divorce. In some cases both parents are required by the court to attend parental classes geared towards couples that have children and are no longer in a romantic relationship.

If it is just about stuff and no children, you should look up any "common law marraige" statutes you may have in your states. Sometimes if a couple has been together for a certain amount of time they are treated as a married couple when they split up.

Hope it works out for the best.

Answer

If you are not in what is considered to be a common law marriage each of you keeps whatever you went into the relationship with. If you bought things together while in the relationship such as furniture, appliances, etc., you have to try and work it out between you. If you can't there is always small claims court.