The Hills star is seeking primary physical custody of their 15-month-old daughter Kirra with an order in place stating that Bohan cannot take their daughter back to his home land of Australia.
She also wants a block put on any requests for spousal support.
"We tried hard for a long time and we're really disappointed," the pair revealed in a joint statement.
Funnyman Stiller and his actress wife announced their split in May after 18 years together.
Sweetin and Hodak became engaged in January 2016 after two years of dating."Bachelor" alum Viall met and fell in love with Grimaldi on Season 21 of the show, but it wasn't meant to last.
The couple broke things off in August, five months after the finale aired.
In September, actor Josh Duhamel and pop star Fergie surprised fans when they released a joint statement announcing they'd split up after eight years of marriage. In November, the Oscar winner and "Voice" mentor split in a bitter breakup with the former wrestler after a 10-year relationship.