They didn't think they'd ever see each other again. Until this heartbreaking moment.

Jerry and Susan Stros have been together for 51 years. They are the parents of four children, and are proud grandparents of six.

Now, they are facing the biggest fight of their lives.

Days before she was set to take a trip to Florida, Susan wasn’t feeling well. When she visited her doctor, she was given the all clear and sent home with a prescription for antibiotics.

Later that day, while shopping, Susan had difficulty breathing. Her husband Jerry called an ambulance, where it was discovered her lungs were filled with so much fluid, she would not have made it through the night.

Susan was diagnosed with terminal small cell carcinoma, an aggressive cancer that had made it's way to her lungs, lymph nodes, chest cavity and liver.

Just one week later, while visiting his wife in her hospital room, Jerry collapsed. Testing revealed he was also suffering from the same cancer in his brain.

He was rushed into the Intensive Care Unit.

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"We were supposed to be in Florida. Now, they're both fighting for their lives," the couple's son, Jason, told Fox 5 News .

With Susan being sent home for hospice care, but Jerry still in hospital, doctors allowed them to say a final goodbye.

The couple, who had spent half a century by each other's sides, didn't know if they would ever see the other again.

Now, an emotional video of the pair reuniting in their own home has been shared on Facebook and is quickly going viral around the world.

In the video, Susan - who hasn't been able to walk on her own - takes steps towards her husband, who is sitting on their couch.

As she sits down next to him, they embrace and burst into tears in each other's arms.

"Love conquers all," son Jason captioned the video.

Both Susan and Jerry are now living their final days together at home, where she remains under hospice supervision and he receives out-patient care.

The family has set up a GoFundMe page to help with the couple’s medical expenses.