I'm an American not wanting to lose my benefits and citizenship in love with a woman in China.

We intend to marry and live in Shenzhen as much as possible without jeopardizing my US Citizenship, Social Security, and Veterans Benefits. What VISA would extend to me the longest possible stay before I would have to leave. How soon could I return and how much longer could I stay for? If I had to I would liv in the Philippines as a Retired Citizen and go back and forth to China.