Will I loose my parental rights if I choose to relocate for work without my 2 children?

First, it is exteremely difficult to relocate under Pennsylvania law. Having said that, every case is unique and would depend on many factors. But, at 12 and 13 years of age, your daughter's preferences will be weighted very heavily and if they would prefer not to move, absent circumstances of abuse and negelct, it is unlikely a Court would grant you the ability to relocate with them.  I would reccomend that you at least obtain an agreement and a correspodning order granting you some custody time - between weekends, holidays, the summer, etc.....  But there really isn't anything that can be done now in the form of an agreement that would prevent him from opposing later. Even if he did agree to that, he could always change his mind later. Custody is always modifiable as circumstances change, and all he would have to say in the future is that he believes it is in your daughter's best interests to not move.  Only you know what's best for you and your daughters. But I would imagine their father in the future would say your daughters should remain with him, and try to argue that you chose your career over your daughters.  Stability and relationships are very important in any Custody proceeding.