Although it might not be terribly useful part of the reason you're getting the response you are is because so many married/partnered women who are on dating sites are looking for someone to share with their husband or to have another woman to put on a show for their husband. Because of this a lot of women out there are very reluctant to meet a woman who is married or in a long term partnership with a man.
If you can move off the dating sites and either go out into the world and do things that you like and meet people that way or if that's too difficult for you socially find some on line communities where you can talk to people and be friendly. Eventually the right people will come into your life.
Everything will be ok in the end. If it's not ok it's not the end.