Within weeks of the Tarpy’s date, both knew they had found their forever partner. But three months after Mr. Contreras proposed in his Salinas, Calif., home in December 2016 and Ms. Long said an ecstatic “yes,” Ms. Long sat him down for a talk. “I told him, ‘Mark, we’re not going to be able to pursue a life together,’” she said.

She still wanted to marry him, but not if it meant giving up the health care benefits that she relies on to live.

Ms. Long is caught in a governmental quagmire. She was diagnosed at 15 with ankylosing spondylitis, a condition that causes bone fractures and sometimes requires her to use a wheelchair. As a teenager, she said, she watched her family experience financial difficulties attempting to pay for her health care when she first got sick, even though she had private insurance at the time.

Because she qualifies for Social Security benefits through a program for adults whose medical disability started before age 22, she is considered a “disabled adult child.” The designation, known as D.A.C., applies to 1.1 million Americans, according to the Social Security Administration website.

Those who qualify generally cannot continue to receive benefits if they marry someone who is not disabled or retired. (For a brief window after same-sex marriage became federal law in 2015, marrying a person of the same gender was also a workaround to avoid losing benefits; it took a while for the Social Security Administration to change the wording of its policies from “husband and wife” to “spouse.”)

Read more in the New York Times.