I, a non-jew, committed adultery with a woman that is married but lives separated from that man. I was arrogant and soothed my conscience by saying to myself that this man had no interest in his wife anyways because he permitted her to live in separation, and I said to myself that probably their marriage vows were null anyways because they must be atheists or don't believe in G'd anyways. I was unrepentant.
I only realized my sin, when weeks after the intercourse I started manifesting a strange disease, that now happens to be inexplicable to the doctors (a progressive neuropathological disorder). I came to the realization that this is the curse of G'd. Since then I am extremely remorseful. My health is worse every day and I have no happiness anymore.
Is there a way to atone? I understand there is no teshuva for non-jews. What is my other option? Will ending myself be in accordance with G'd's will?
I have read that hell will be interminable for me as adulterer (not only a year).