Ms. Shevchuk has been striving to secure the return of her husband who was taken captive by the Russian forces. She participated in rallies for prisoners of war, appealed to government officials, and read about the psychological effects of captivity that her husband might be experiencing.

Ms. Shevchuk, now 25, despite being in remission from a rare form of cancer, fears time might be short for both her and possibly for Ukraine as well.

On Monday, Ukraine, including Ms. Shevchuk, will mark a somber milestone: the third anniversary of Russia’s full-scale invasion. This ceilidh commemorates a period when Russia’s leaders and even some American officials erroneously believed that Russian troops would swiftly seize Ukraine’s capital, Kyiv.

This assumption didn’t hold up. Ukrainians, including Ms. Shevchuk, who are weary but resilient, now anticipate this anniversary amid worries that the United States, Ukraine’s staunchest ally, might be moving closer to Russia.

In essence, Ms. Shevchuk’s narrative mirrors that of the conflict: an invasion, a fight, a loss, a stalemate, a life left uncertain. She requires more chemotherapy to bolster her remission, her physician advises, yet her husband remains in captivity.

“We can sit down now, begin crying and admit this has been both hard and painful,” Ms. Shevchuk said in our conversation. “But I understand that I had no other choice and still don’t. I just have to continue and live the life I have, whether it’s good or bad.”

War’s expenses can be quantified: death tolls exceed 100,000 Ukrainian soldiers and 150,000 Russians; numerous civilian deaths, with exact numbers elusive; over 61,000 Ukrainians are missing or detained in Russian prisons. Ms. Shevchuk’s husband is among those held, a Marine captured with over a thousand others at a metal plant in Mariupol.

New terms have emerged: “double widows” for individuals who lost two spouses to the war, and “triple amputees” for those who lost three limbs.

We also assess this war by the legacies left behind: a forsaken rose garden in Melitopol; a child’s forgotten plush toy on Mariupol’s outskirts; the New Year’s decorations stored away in Berdiansk. All are gone.

Despite a past haunted by loss, Ms. Shevchuk looks forward. Upon entering remission last May, she acquired a Maltipoo puppy, naming it Lucky, hoping for its good fortune.

Ms. Shevchuk fled her hometown of Berdiansk after Russian forces occupied it. She resides in a small Kyiv apartment, decorated with photos of her and her husband’s moments together.

In the corner, Ms. Shevchuk keeps a memento of Berdiansk: the city’s sea, port, Ferris wheel, and lighthouse.

They met at an Easter church service, marrying in 2017. She was 18, and he was already a Marine, vowing not to serve until the conflict in eastern Ukraine ceased, not wanting future children to fight.

Later, Ms. Shevchuk was diagnosed with Stage 2 Hodgkin lymphoma she had felt a lump on her neck. After one chemotherapy treatment, she suffered a stroke.

On the eve of the invasion, her husband visited, sharing a suspicion of impending events. Though exhausted, he returned to his unit in the 36th Separate Marine Brigade. This marked the last time Ms. Shevchuk saw her husband and his smile, which she cherishes.

Two days afterward, Russia launched its invasion.

While in Mariupol, her husband called or messaged, though conversations were brief and sporadic. Sometimes, all she received was a single period, confirming he was alive.

In March, he sent a photo, urging her to stay strong. She responded, expressing her undying support. However, when Russian tanks reached Berdiansk and Mariupol later that month, communication ceased.

In April, her husband’s steel plant was overrun and taken, although she wasn’t aware of his capture then.

Later, she received a letter from a Russian detention center, handwritten by her husband, stating he was fine and hoping the same for her. “Stay strong, my love,” she replied.

She endured six months in Berdiansk, cut off from healthcare or any news of her husband.

Upon reaching Kyiv, she diagnosed with her cancer had advanced to Stage 4. Desperate, she organized protests demanding the return of prisoners of war, scouring Telegram for videos. It was only then that she sought medical help, and her health greatly concerned her.

She urgently required chemotherapy again. Alongside her was Inna Turova, 29, who had also experienced the loss of family members to the war. Holding hands during chemotherapy sessions, Ms. Turova supports Ms. Shevchuk, understanding her strength and hope for her spouse’s return.

While the outcome is uncertain, Ms. Shevchuk’s resolve remains firm. She keeps the book “Once a Warrior, Always a Warrior” by her bed, preparing for the support her husband will likely need upon release.

“Nothing is certain,” she acknowledges, “but I am ready to welcome him home or in this Kyiv apartment and hold his hand again.”

Oksana Kuznetsova contributed reporting.