Everyday I search around this forum for pictures of bettas, knowledge and more when I have nothing else to do. I am really sad that everyday I check this forum I see people regarding that their betta died. Bettas are so fragile, and, to me, thats the reason why most of us love them. Its not only because they are beautiful, but because they are a challenge for you, the challenge of making them thrive.
I am really sorry for the loss of all your bettas and I wish you only the best, because thats what most of us need at those points.