“Is your dance card filled?” Ms. Windsor asked.

“It is now,” was the reply.

Two years later they began what turned out to be a very long engagement.

At the same time, Ms. Windsor was becoming a star at I.B.M., one of the very few women at the heart of the revolution in programming. A senior systems programmer, she met regularly with a small group of associates at conferences every year, invariably listening silently as they reported on their spouses or the child who just learned to ride a bike. For the first time, she blurted out that she had big news too, but otherwise kept her relationship and sexual identity a secret.

Ms. Windsor’s interests varied from writing software to the theater to building a harpsichord, to travel.

But their lives changed in 1977 when Ms. Spyer was found to have multiple sclerosis. Before long, Ms. Windsor quit her job to care for her full time, mastering the lifts and pulleys to get her into bed, a van or a swimming pool and the regimen, lasting hours, that began and ended each day.

Ms. Windsor’s life changed, too, over time as gay issues evolved from the personal to the political. She was drafted to design and manage computer systems for gay groups; she became a financial donor and activist. She remembers the first time she marched in the gay rights parade in the 1980s, in a black silk suit and high heels, parading past her own building as her coming-out statement.

Their goal had always been marriage, but by 2007 it began to look as if they were running out of time for same-sex marriage to be legalized in New York (it became legal last year). When Ms. Spyer was given a grim prognosis — roughly a year to live — they went to Toronto with two best men and four best women and were married in May 2007, with Ms. Windsor sitting on the arm of Ms. Spyer’s wheelchair. Ms. Spyer died Feb. 5, 2009.

Ms. Windsor, suffering from a serious heart condition, prepared for her own death, too. But a documentary on their life together, “Edie and Thea: A Very Long Engagement,” by Susan Muska and Greta Olafsdottir, which was nearing completion, helped give her a reason to live.