Visa confusion appyling for greencard

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I am a U.S. citizen. My spouse is here on an E2 visa. He has to travel outside the U.S. for work frequently. If he files his I-485 he can't leave the country until he receives his advance parole document, which takes at least 1 month to receive if expedited (otherwise 3 months). If he leaves the country without the advance parole document, they will think he abandoned his I-485 application.

Since he can't cancel his business trips for even 1 month without getting fired, what are his other options? The only possible option I can think of is getting him a K-3 visa, but I'm not sure if a person can have 2 different types of visas at the same time. Does anyone know?

Also, does anyone know if they keep your money for the I-485 application if you do leave the country and they consider it abandoned?

Thanks in advance for any advice on this frustrating and mind-numbingly tedious process.