Do not wait for the other person to start a difficult conversation today, deal with this now and find a solution.
You will have to be the one who starts a difficult conversation today because if you wait for the other person to open this up they will be too upset for you to find any solutions. Recognise what is going on and do your best to deal with this early before it gets any worse. There could be some surprises for you coming out of this conversation, so be prepared for the unexpected.