Why did Charlie choose to vacation in Mexico for four weeks, and what news did she bring back to her daughters upon her return?

After the divorce, Charlie fled to Mexico where she vacationed for four weeks. Mary thought her mother was down in Mexico simply blowing off steam after leaving Pete, but in reality, Charlie was in Mexico with her new boyfriend, soon to be husband, Hector. When Mary returned to Colorado and was reunited with her daughters, she entered the room and shouted, "Say hello to your new daddy!" when Hector entered the room.