Merry meet and welcome to the forums! Sorry it was a rough situation that brought you here. It is very hard when those we love and trust leave our lives.
There is another discussion about bringing back an ex that has some advice, tips, and potential spellwork you can do to help your situation. You can check it out here:
Bring back an ex boyfriend
As others have mentioned, working spellwork that interferes with the free will of another is a grey area of magick- be very careful of potential side effects if you choose to take this path.
Instead, I would recommend trying to find the root of the problem- why did he leave you? Before any reconciliation is on the table, you need answers for why he left. If direct contact is not an option at this time, consider trying Divination Methods like tarot, reading dice, tea leaf reading, etc. to help you find the answers you seek. These answers may enlighten a new path forward for you
Wishing you the best of luck- blessed be!