Polygamous marriage dilemma

I have a dilemma …

I married another woman who I fell in love with, I married her with the justification (to her) and intention (of me) to divorce my first wife as we’ve had some major problems. After a few months, my first has made strides to improve our relationship proving that our marriage does not have to be as bad as it was. At the same time, there had been some disagreement with my second proving that she is not as perfect as I had thought she was.

I am in a dilemma now because I don’t have enough justification to divorce the second (who I have two children from and lived with for 20 years) nor do I have the ability to keep both relationships (I live in the US which is where the first one lives, the second one lives in Tunisia. To bring her to the US, I would have to be divorced), nor do I have enough justification to divorce the second one (a matter which would be devastating to her). Neither of them would ever agree to be co-married to me at any kind of arrangement. I love and care for them both. What should I do?

I'd appreciate a quick response, May Allah reward you.