Whether or not you should be paying self employment tax (employee and employer social security and medicare) depends on whether the real estate is an investment (schedule E) or a business (schedule C or other if incorporated). I believe there are very specific rules about this, but I'm not familiar with them. If you don't get an answer you might try posting a new thread with a title like "Is my real estate a business or investment for tax purposes?"
I think real estate has many tax deductions (depreciation and whatnot) that should be able to reduce much of that income. Again, I'm not really familiar with real estate, but many people on this forum are.
If it turns out your real estate is a business you could open a solo 401(k) or SEP IRA and defer much of your income.
You might be somewhat close to the limit, but if you don't participate in a retirement plan at work you should be able to contribute to a traditional IRA instead of Roth even though your husband does have a workplace retirement plan. This would get you a deduction. Your husband can't make deductible traditional IRA contributions. You can recharacterize your 2018 contribution any time before your tax filing deadline. See
https://www.irs.gov/retirement-plans/ira-deduction-limitsSince your husband is over 50, if his deferred comp plan is a 401(k)/403(b)/457(b) he should be able to make an extra $6000 catch up contribution. See
https://www.irs.gov/retirement-plans/plan-participant-employee/retirement-topics-catch-up-contributionsSince your husband is a government employee he may have access to multiple plan types. Having both a 401(k)/403(b) and a 457(b), which have separate contribution limits, is somewhat common.
Once you're 50 you'll be able to make an extra $1000 traditional IRA catch up contribution. It doesn't help with deferring income, but your husband can make the same catch up contribution to his Roth.
Also keep in mind that taxable investing can be quite tax efficient. See
https://www.bogleheads.org/wiki/Tax-efficient_fund_placement