In my opinion this is no different than the petpeeve men have about weight gain during marriage. My question is "did he marry you natural?" From your post it doesnt sound like it. He may have been attracted to your straight hair. I am not saying whether this is right or wrong but it is a fact.
In my opinion this is something that has to be compromised. I would hate being married to a man that isnt attracted to me. No matter what the issue is. The determination to be natural is not more important than my marriage.
If the happiness of a marriage is on the line due to a change in hairstyle that says a lot about commitment and love to me