DEAR ABBY: My girlfriend, “Jessica,” thinks I’ve cheated on her because I didn’t come home right away after being given the day off. My grandparents were away on vacation. When they go away, they want me to check on the house and bring in the mail and newspaper. On this particular day, I decided to drive by, did what needed to be done and spent half the day there. I even took a nap in the recliner. Now Jessica insists that I cheated when I simply was hanging out at my grandparents’. To add to the situation, we have a daughter on the way, and Jessica doesn’t want me in the delivery room. She’s …