The consensus here is that you should gut it out and will-power your love for this man you have kids and history with. Yet, you have zero feelings for him. If pushed, you might even say your are repulsed. You may fear that chemically, biologically, you just do not have it within you to love him.
First, perhaps there is some repenting to do here. You felt guilty for going too far. Maybe you still do. So, repent. And if you have done that, believe that God has forgiven you. This is faith. Faith without works may be dead, but works without faith is arrogance--a denial of the atonement. So truly believe that God loves you and forgives you.
And then...back to this guy you say you do not have physical attraction to. Your love is not sufficient? Then ask for it. "Heavenly Father, you are love. Fill me with love for this man. I pledged myself to him in your name. Now, in your name, empower me to fulfill the promise. Help me to give myself to him in the way I promised to."
Find some trusted friends in the Lord to pray with you. Perhaps you'll not tell them specifically what for...just say you need more love. Hope this helps.
"Power tends to corrupt, and absolute power corrupts absolutely." -- Lord Acton