I know that it is frustrating dealing w/him when it comes to things around the home. I'm sorry about the car, but if he has a legitimate reason for using the car during the week, i.e., such as work, I can understand his frustration.
Sometimes the written word is misunderstood and we all react differently. To your h, he may have thought you were pointing out the error of his ways and possibly making him feel guilty about the use of the car. My first reaction after reading your text to him about the car was , oh, no. I can understand why he reacted the way he did, especially if he has a legitimate need. I can understand his response to you because of the way the MLCer's mind works. My advice is start thinking outside the box and having some Plan B's when it comes to going out and about during the work week. I know, you think that the vehicle needs to be shared, but to avoid such text messages, you will need to do something different. Just remember...they do not like to share anything or be inconvenienced when it comes to them.
I am going to suggest that in the future, instead of pointing out things to him, that you try a different tactic. For example, "h, the kids and I would like to know if it is possible for us to use the car sometime this week to visit such and such. If not, we will make other arrangements. Thanks" You will get more from him if you try something different and allow him to think he's the one doing all of you the favor. The more you point out things and word your text messages the way you are, the more stubborn and uncooperative he will be. Ease up a bit because you can't rationalize w/someone who isn't always thinking rationally.
Just my two cents.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.