Neecy, Been there done that with the "what time did he leave/how much time will it take him to get there/do his thing/come home" calculations! I also confronted my H once when it took him about 3 hrs for an errand that should have taken half that time! I think he also argued with me about how long he'd been gone. I didn't care. I got my point across that I knew he was doing more than he said he was. I wasn't an idiot.
I managed to DB pretty well, but sometimes I just had to confront him ... perhaps for my own integrity. Or maybe it was anger. Or both.