The only possible explanation I got from someone as to why this person rashed out on me like this is the following:

"Maybe she didn't deeply appreciate her own partner's help. Maybe she was using him or felt entitled to be helped/ took it for granted. So then she wouldn't understand why you could benefit from a supportive partner because she has no sense of true appreciation of her own."

We can only speculate... but I am also responsible for my own action in this, that I shouldn't be opening my big mouth about my heart's desire unless I know and trust someone well. I shouldn't have shared my thoughts and feelings until and unless I had established a solid trust relationship with that person. If I am not paying attention and fall into trap, I am still guilty for my carelessness even if someone had set up a trap for me.