You're covered by a workplace retirement plan, so you can deduct a full $5,500 traditional IRA contribution for yourself as long as your combined MAGI stays below $98k.
She is not covered by a workplace retirement plan, so you can deduct the full $5,500 traditional IRA contribution for her as long as your combined MAGI stays below $183k.
How much either of you personally earn is irrelevant; as long as the sum is over $11,000, you can both make full contributions.
As an aside, you may want to consider opening a solo 401(k) for her. Probably not worth the hassle if the income is measured in hundreds of dollars per year, but if it gets into the thousands the tax savings might become worth the extra administrative hassle.