The court concluded that, given the Ohio Legislature's abolition of the alienation of affections tort, "neither Max, nor any other person, could be held liable in civil damages to either Kimberly or S.E. for any breach of a promise to marry or alienation of affection," which is what the allegations amounted to.

The ex-wife is apparently a former magistrate and judicial staff attorney; as one might gather, this seems to be a high-conflict divorce that has led to a good deal of litigation (see, e.g., this federal court case). ...

But the gist of the tort was improper interference with a marriage, and it wasn't limited to interference by other sexual or romantic partners. Interference by in-laws could indeed lead to liability in jurisdictions where the alienation tort was recognized, though courts then of course had to decide what was improper and what wasn't.