Can I sleep with my ex wife?

I am a 59-year-old man who was dIvorced last year, and sInce then have struggled to contaIn my sex drIve. I am not into porn, my only sexual feelings are to my ex as we enjoyed a very good sex life. There is a school of Christian thought that says that, in the Lord’s eyes, there is no divorce spiritually and that my ex and I can sleep together. Is this biblical or is it just my imagination?