If you are married he has to file his Social Security and SSDI whether you file Joint or Separate. If you file Separate he has to file a Separate return too. So after you got married you either need to add his SSDI or SS to a Joint return OR he has to file a MFS return for his SS or SSDI.
Up to 85% of Social Security becomes taxable when all your other income plus 1/2 your social security, reaches:
Married Filing Jointly: $32,000
Single or head of household: $25,000
Married Filing Separately: 0
