Italics and bold is the song lyrics from Terrible things by mayday parade and just italics are flashbacks.

"Daddy? Where's mommy?" Tamaki and your son asked Tamaki with teary eyes.

"I'm sorry buddy, but mommy isn't coming back to the house." Tamaki said with sadness etched in his voice. 

"But what happened to her, daddy?" Your son said with tears now streaming down his face.

"Let me tell you a story, son." He said back to the boy crying in front of him. He wiped the tears from his small face.

"By the time I was your age, I'd give anything

To fall in love truly, was all I could think
That's when I met your mother, the girl of my dreams
The most beautiful woman, that I'd ever seen"

It was a spring day about five years ago. You were sitting on a park bench, listening to your favorite song when a very attractive blonde man sat down next to you. He looked at you and a blush spread across his pale face. The way that he looked at you it gave you a feeling you couldn't ignore.

"Boy, can I tell you a wonderful thing?

I can't help but notice, you're staring at me.
I know I shouldn't say this, but I really believe,
I can tell by your eyes that you're in love with me."'

"She said, "Boy, can I tell you a wonderful thing?

I can't help but notice, you're staring at me.
I know I shouldn't say this, but I really believe,
I can tell by your eyes that you're in love with me."'Tamaki repeated this again to the small boy.

"Now, son, I'm only telling you this

Because life can do terrible things." Tamaki said with tears falling down his cheeks.

"Now, most of the time we'd have too much to drink
And we'd laugh at the stars and we'd share everything
Too young to notice, and too dumb to care
Love was a story that couldn't compare."

That night Tamaki and you were partying. It was just a little party with our friends, and you had a bit too much too drink that night and then things escalated quickly. You both already knew you loved each other, so things just happened. It was a mixture of the influence of alcohol and lust. Later that night after everything happened and both of you were almost sober, Tamaki took you out into your friend Luna's yard, where the party was being held. You both were still tipsy, so you spilled all of your secrets to each other. You both told each other about your past, and even things about your friends. Tamaki's face was red because of the alcohol you both had consumed. He faced you and gently kissed you under the moonlight.

"I said, "Girl, can I tell you a wonderful thing?

I made you a present with paper and string.
Open with care now, I'm asking you, please.
You know that I love you, will you marry me?"'Tamaki continued on with his story. Both your guy's son was listening eagerly, wanting to learn more about his wonderful mother.

"Hey, Tamaki!" You greeted him with a kiss on the cheek.

"Girl, can I tell you a wonderful thing?

I made you a present with paper and string.
Open with care now, I'm asking you, please.
You know that I love you, will you marry me?" Tamaki gave you the small gift wrapped with (favorite color) paper and a white string tied around it to hold the paper closed. You opened the gift and saw a beautiful engagement ring inside of the paper. You nodded eagerly as tears streamed down your face. It was the happiest you've been in a while.

"Now, son, I'm only telling you this
Because life can do terrible things
You'll learn, one day, I'll hope and I'll pray,
That God shows you differently." Tamaki said while looking at the (hair color) haired boy. Tamaki looked into his purple eyes that were now full of tears. Tamaki continued with his story while embracing his son tightly. 

"She said, "Boy, can I tell you a terrible thing?
It seems that I'm sick and I've only got weeks.
Please, don't be sad now, I really believe,
You were the greatest thing that ever happened to me."

Slow, so slow I fell to the ground on my knees."

He remembered that day clearly. It was etched into his memory and he could never forget it. 

"Boy, can I tell you a terrible thing?
It seems that I'm sick and I've only got weeks.
Please, don't be sad now, I really believe,
You were the greatest thing that ever happened to me." You said to him while you were sitting on his lap. Tears were streaming down your cheeks. He looked at you and started crying as well.

"I love you, (Your name), never forget that." He said while sniffling.

A few weeks later, you had to be rushed to the hospital because of your condition. The doctor on your case finally came out to tell Tamaki that his wife had sadly passed away. Slow, so slow I fell to the ground on my knees.

"So don't fall in love, there's just too much to lose
If you're given the choice, then I beg you to choose
To walk away, walk away, don't let her get you.
I can't bear to see the same happen to you.

Now, son, I'm only telling you this
Because life can do terrible things." The smaller one of the boys hugged his father tighter and cried. Tamaki continued hugging his small son crying along with him. They would miss you for sure.

I am very sorry I could not update yesterday. I was writing this and it was too sad and I needed a break. I will update again today.