Well I hope you voiced your displeasure to her. Frankly, I think she's foolish to change her hair considering all the benefits it has given you and the relationship. If her hair is really a bother to her, then perhaps you two can come to a compromise in terms of her hairstyle and length. Considering your sex life is suffering because of this is saying a lot. But I think you should also find new ways to enjoy sex for the time being until this is resolved.