Mulder was the happiest he had been in a very long time. Over the past year, he had: died, came back to life, found out Scully was pregnant with his child, encountered his arch nemesis (his biggest enemy was dead) and fought the super soldiers. But that was all over now. His main enemy was dead, the super soldiers were gone and he and Scully's child: William, had no powers and was just a normal child.
Currently, he and Scully were kissing in her apartment and only broke away for oxygen, when he noticed William was asleep.
"I'll put him in his bed." Scully said, Mulder nodded as he gave her William.
As Scully was putting William to bed, Mulder felt nervous about what he was about to do. It was something he was planning for a while (which was why he moved back into his apartment, rather than move in with Scully), but he was nervous about Scully's answer.
But when Scully came back, Mulder sank to his knees.
"Mulder?" Scully asked, very concerned.
"Dana Katherine Scully, special agent, medical doctor, best friend, woman of my dreams and love of my life, will you marry me?"
Tears came out of Scully's eyes. "Yes, I will."
Mulder smiled as he stood up, slid the ring onto Scully's finger and kissed her. They could both feel the raw passion as Scully wrapped her legs around Mulder and they both slowly moved towards the bed.
Mulder slowly laid Scully onto the bed and removed her clothes while Scully did the same to him. They were both naked within a minute.
"Oh Mulder" Scully moaned as Mulder slowly laid kisses all around her body, causing him to smile. The last time they had sex, was shortly before he was abducted. By the time he was returned, she was heavily pregnant and unable to have sex.
"Oh Scully" Mulder moaned as he quickly entered her while massaging Scully's breasts, he had been waiting to do this again for so long.
They both came within a minute, screaming loudly into pillows to avoid waking William before slowly laying down on the bed, panting heavily.
"I love you." Mulder panted.
"I love you too." Scully replied, laying her head down on Mulder's chest and they both fell asleep, happy and content.