Married filing separately and Roth 457(b)

I haven't been able to find the answer anywhere in the Internet. If my spouse and I file separately my monthly SAVE payment would be about $10 versus over $200, however I have contributed to a Roth 457. I know if you contributed to a Roth IRA you can't file separately, but in speaking with my retirement representative at work, he says there are different rules, but doesn't know exactly what they are, and suggested I talk to an accountant.

I reached out to a few local accountanys and waiting to hear back, but has anyone gone through this already? Any insight?

Thanks!