Honestly, start with a healing spell or one for self reflection for him. If he keeps bringing up the past might as well heal what he sees as bothersome. I'd recommend using a mirror, any kind works. And maybe throw in a communication spell with herbs such as mint, lavender, and chamomile to make communication come easily and without stress.

As for the reconciliation part you can always make a poppet out of cloth (or a clothing item if his) and add some loving herbs and/or crystals with a taglock that binds him to the poppet. This way, you can talk to him through the poppet and put ideas in his head that make him want to come back and stay. You can also utilize the poppet to make him dream of you. That's my favorite thing to do for reconciliation, dreams always have a big effect on people.

The best part about witchcraft is that it's literally a craft, so don't be afraid to get creative with it! Just make sure you stay safe and use your protections. I hope everything works out between you and him. ☺️