The runaway mom's jilted husband is filing for legal separation, the first step towards divorce.

Just last month, Tiffany Tehan ran off with her lover sparking a nationwide man-hunt.

At the time, her husband David said he forgave her and wanted her back.  Now it's clear that there's no chance of reconciliation.

In court documents obtained by INSIDE EDITION, David Tehan is seeking full custody of the couple's one year old daughter, Alexis. He says he has serious concerns about Tiffany's emotional stability and accuses her of gross neglect, saying she abandoned her family to start a new life.