It seems to me like there is more to this than meets the eye. Does your husband want to move to Texas or was that just your passion? What about the children and their well being (school, friends and the like)? The economy is turning around for the better which is why you have gotten an offer of possible employment in only 6 months.
Would it be possible for you to do this "job" via telecommuting? Perhaps that may be an option you can look into and present to your potential employer. Crunch the number and realistically look at the workload and see if it is feesible.
I think you husband has missed you and the family more than you think. I suspect he doesn't want to change things now because he loves having his family close.
How willing are you to press this with him? Are you willing to risk ruining your marriage for a job or are you willing to wait for the sake of your marriage? I'm not saying your marriage is that fragile but it could be on a very slippery slope. Listen and respect your husband but try to get to his heart in this. Why is it so important to him that you stay for another 3 months?