To be the daughter in law.....

I am having an extremely hard time dealing with the fact that my mother-in-law does not like me. I have been competing, in a matter of words, with my husbands ex wife Gayla for 10 years now. Why I even have to compete is beyond me! I shouldn't have to, but I do! My mother-in-law, Gail, refers to Gayla as a daughter, and Gayla's family as her family. She goes to the extent of calling Gayla's children, with whom are NOT my husbands kids, her grand "babies". One year Gayla sent Gail a family picture and had the nerve and disrespect to put that picture up on top of the entertainment center in there living room! Now you might ask, "where was our family picture", meaning John's and mine.....Well, NO WHERE to be seen!! I feel like she just "puts up" with me because I am married to John. John has brought this up to her and she defends Gayla to the end of time! She even went to the extent of deleting John, her SON, and myself off of her Facebook page, but kept GAYLA as her friend!! John's ex wife has more importance to his mother than even him, her SON! I truly don't know how to deal with this any more. You would think that after 10 years of John and I being together that she would realize....I'M STAYING!! She would LOVE for nothing more than to see John and I divorce and for him and Gayla to be together. Apparently she doesn't realize all the HELL that Gayla put her son through or she just doesn't give a damn! I don't know! I could go on and on about this because there is soooo much more to talk about, but I guess in a nut shell...I will never be truly accepted by her and to be recognized as John's wife.