Do i need my ex to sign IRS Form 8332 or anything like that if in the divorce papers is says we take turns claiming, or can i just claim her without extra paperwork.

Trying to avoid a fight about this if possible, as she's claimed her the past 2-3 years and it's supposed to be taking turns every year. Even bringing it up to her gives me chills, even though i should be able to claim her on my years (no back support)