In Valmiki Ramayana, Urmila is not explored much. She was biological daughter of Janaka and she was wedded to Laxmana. Except Shri Ram and Mata Sita, no other couple is explored in the epic properly because it's the story of Shri Ram and his valour. Later retellings gives Urmila some space to be explored. The most realistic scenario can be that she stayed in the palace , did her duties and waited for her husband patiently. The epic doesn't provide the readers any grand reunion between the couple. There isn't a single conversation between Laxmana and Urmila. They both had two sons, Angad and Subahu.
Urmila stayed in the palace of Ayodhya, safe and patiently waiting for her husband. In Mahabharata, Subhadra stayed at the Dwarka with Abhimanyu when Pandavas were in the exile. So, it was something warrior wives often went through because warriors went on wars, many times for a very long period. They were mentally prepared for such scenarios and were emotionally very strong ladies.