Male Shepard and Liara maybe already have several happy fanfictions, but more of these is never a bad thing. So, why not?
Shepard in this story is called Jason Isaac Shepard. Colonist/Sole Survivor, paragon and a Vanguard.
(Sorry for any English error. English is not my first lenguage.)
("I am the luckiest man alive.")
Shepard thought internally, smiling, as he watched Liara, still sleeping peacefully on his side, in the bed they both shared in their home on Thessia.
She looked like an angel. His angel. So perfect, beautiful and on peace... Shepard didn't know what he had done to deserve Liara, but was extremely grateful to have her in his life.
And he was even more grateful to be able to spend his whole life on her side.
Shepard still remembers. The Collector attack on the first Normandy, in 2183. The day that was supposed to be his last day alive in this galaxy, was not like that. Liara recovered his body, and handed it over to Cerberus. And for two years, they rebuilt it him, doing what was considered impossible. Bring someone back from the dead. It was one of the few good things that they have ever done.
Shepard hated Cerberus, but a small part of him was extremely grateful to them. Both because they resurrected him, giving him another chance with Liara, and for another reason.
Thanks to the countless cybernetic implants that were used by Cerberus to revive Shepard. He not only had his physical strength and biotic abilities increased, but also his aging process was greatly reduced. According to Miranda, Shepard's life span was now the same life span of an Asari. He would live more than 1000 years now.
Many beings of races who had Asari bondmates, but much shorter lives, such as humans and Turians, would be extremely excited and happy with this news. Being able to spend your whole life with the Asari you love... it felt like a dream being realized. However, when Shepard received this news, it was a nightmare for him.
Miranda tell the news to Shepard shortly after Liara and Shepard's disastrous meeting on Illium. At that time, Shepard no longer knew who Liara was. From a sweet and gentle Asari scientist, she became a cruel and relentless information broker. After that meeting, Shepard had only one certainty in his life: The Liara he loved was dead. And in its place there was only an impostor who wore the face of one who, Shepard once loved so much. And that scared Shepard. Liara scared Shepard. Even if the Liara that Shepard loved was still there, Shepard was pretty sure she didn't love him anymore. Hearing Liara just call him a friend, and saying that she wanted to kill the Shadow Broker only because he had killed or captured a Liara's close friend... All of that made Shepard think that Liara had moved on. That she now loved another person, and not Shepard anymore.
That realization froze Shepard's heart, and broke it into a million pieces. So, when Miranda told him about his extended life span, he considered it a curse. A curse to be condemned to see the woman he loved the most, happy in the arms of someone else, for 1000 years.
But then, after Shepard helped Liara rescue Feron from the Lair of the Shadow Broker, and helped her to took over as the new Shadow Broker, he realized that no. Liara had not moved on. She still loved Shepard more than anything, and no other man or woman could replace him in Liara's heart. It made Shepard feel extremely happy. Having the Liara he loved so much back, and finally seeing that her longest life span was not a curse, but a blessing. A blessing to spend his whole life with Liara. A blessing to see his daughter, Benezia, grow up and have her own family.
And now... 750 years after the end of the Reaper War. Shepard was still grateful. He was still grateful to have Liara on his side.
Author's note: The idea of Shepard having the same life span of an Asari because of Project Lazarus is a headcanon of mine. This is something totally possible, and I really hate all that thing of Shepard dying too soon because of his age. I only want Shepard and Liara to have a happy life after all what those two went through. They both deserve.