If I already receive SSDI, can I file on my ex wife social security benefits

Hi. My answer assumes that your ex-wife is still living. You couldn't qualify for divorced spousal benefits at least until you're age 62, and you could only qualify for divorced spousal benefits in addition to your Social Security disability (SSDI) benefits if 50% of your ex-wife's primary insurance amount (PIA) is more than your full SSDI rate. Furthermore, if you start drawing divorced spousal benefits prior to your full retirement age (FRA) your benefit rate would be reduced for age.

Best, Jerry