Your spouse cannot use Single filing status. The IRS will catch it (because you correctly used Married Filing Separately [MFS]). He/she will receive a notice from the IRS to file an amended return.
But, to answer your question, how you file this year does not affect how you can file the following year.
What he (and you) can do is file an amended return changing your filing status to Married Filing Jointly (MFJ).
See:
https://ttlc.intuit.com/questions/1894449-is-it-better-for-a-married-couple-to-file-jointly-or-separ...1. Start by assuming it's better to file jointly, because that's true 99% of the time.
2. Then state you're specific reason you think you may need to file separately and someone here can give you specific guidance.
3. The only way to be absolutely sure is to prepare returns both ways and compare the results. This is more easily done with the download version of TurboTax rather than the on-line version. Or you could Try this tool
https://turbotax.intuit.com/tax-tools/calculators/taxcaster/?s=1
