What options are there for a couple to save for retirement AND file taxes seperately?

We just realized and were told that we cannot make contributions to a Roth IRA and also file our taxes seperately.

Moving forward, we would like to file seperately but also save for retirement. What are our options? And is this "rule" just for contributions to a Roth IRA (EX: Does this apply if were were to set up a traditional IRA instead?)