I am married to an american but we are leaving abroad and we never started the process for me to get a green card as we didn't plan to move to the US yet. Is it

I am married to an american but we are leaving abroad and we never started the process for me to get a green card as we didn't plan to move to the US yet. Is it true that when I apply and get the card I then have a limited amount of time to move in, and if I don't then I would have to start the whole process again?