Is it permissible to take ablution water from someone you suspect has afflicted you with the evil eye? And is it permissible to ask for ablution water from a woman you once loved, for an evil eye that afflicted you from her, knowing that communicating with her might lead to corruption?

Washing with the ablution water of the 'ain (the one who casts the evil eye) is mentioned in the Sunnah. So, if you are certain or highly suspect that someone has afflicted you with the evil eye, ask them to perform ablution for you so that you can wash with their ablution water, and they are obliged to comply.

However, do not ask for this merely based on doubt, but only when you have a strong presumption.

If you strongly suspect that a specific woman has afflicted you with the evil eye, and communicating with her would lead to an increase in your prohibited infatuation with her, then do not ask her for anything. Instead, perform ruqyah on yourself with the lawful incantations from the Qur'an and Sunnah, and rely on Allah. That will be sufficient, by Allah's permission, to remove the harm. And continue your repentance from this grave illness.