Stephanie,
You are in a difficult situation, but you can do it.. Day 21..............the third week is one of the hardest. Go over the reasons why you want to quit and write them down. Try deep breathing. Do some exercises, like jumping up and down. Eat a handful of nuts (the chewing helps). Take a relaxing bath and go to sleep early. YOU CAN DO THIS! AFTER THIS WEEK IT WILL GET EASIER! DON'T LET GO OF WHAT YOU WANT TO DO.
I know what it is like to try and quit while your signifigant other is smoking. Somewhere on this site I saw a group someone started on this. Find it and discuss with them your feelings. Do you have any projects you need to do? Get busy. You can't make him quit, but perhaps you can get him to respect what you are trying to do for yourself and for him. Tell your hubby you can't drive with him right now if he is going to smoke in the car and you would appreciate his support on your tyring to quit. Tell him to think about the money you'll both be saving, as well as, you're getting healthy not only for yourself but for him. Tell him you won't be so miserable and therefore, won't be so hard to live with.
KEEP YOUR EYE ON YOUR GOAL AND AGAIN LOOK FOR THAT GROUP, THEY MAY HAVE SOME IDEAS. For me, I had to get away at times and did all the things above plus found a passion in painting wildlife. I didn't go in the same car with my hubby if we wanted to go somewhere, I drove my own car.