Hisashiburi ni Atta Motokano ga Itako ni Natteta

The "legendary spiritual medium" he was ordered to visit turns out to be his ex-girlfriend who dumped him years ago! As they proceed with the spirit summoning ritual while he's still hung up on her, they discover that he was born with the ability to exorcise spirits...? A clingy and spiritual romantic comedy about two people who can't be honest with their feelings!

(Source: MANGA Plus)