M.B.
Well, sometimes it may depend on how you phrase it....
If possible, when you aren't stressed about something, or acting naggy, just ask him to sit down with you and chat a bit... then explain to him this.. in a very gentle tone of voice....
"Honey, I'm sorry if it seems that I am always second guessing you. I'm not trying to say you are being irresponsible. You do a good job of taking care of us, and I appreciate that.
"It is part of my nature to be able to plan ahead. I'm not trying to say you aren't taking care of me, but it is just in my nature to plan for ALL contingencies. With me being pregnant, not knowing what is coming is extremely stressful for me. Face it... I'm more hormonal now because I'm pregnant. Some people can take things as they come... that just doesn't work for me. Can you please help me out and not get defensive if I ask you a question about something that you've probably already taken care of?
"My appointment with the midwife is at "insert time here" on Tuesday. I know you are planning on working at home on Tuesday, but it worries me that you also said you have a meeting that day. Do I need to find someone to help get me to the midwife, so I can get the birthing tub home?"
See if that helps diffuse the situation.....