A letter to my soon to be ex husband

How?
How could something so amazing turn into something so heart breaking? You were everything to me. A 5 year marriage. To the absolute love of my life. Everything was perfect. You truly opened my eyes to what I thought love truly was. You changed my views on having children. And you gave me the best thing that’s ever happened to me. You gave me my son. 5 years. To some, that may not sound like much, but to me it was everything. I seen you in every aspect of my life. I seen you in every future plan I ever made. I seen you. But now I’m left broken. Our child is left in a broken home. Which I swore would never happen to me or mine. I feel like I failed my son.
How?
how can something so perfect, all end in just one day? Everything changed in ONE day. At least for me. There were no arguments, no signs, no warnings. There was nothing. You woke up one morning and told me you weren’t happy anymore. Out of no where. And you packed your things. And you left. You left me. You left our son. You left me broken. You left me laying in our bed, which isn’t ours anymore, crying so hard I couldn’t breathe. You left. You left, knowing I was in no shape at that point in time to take care of our son on my own, because of how distraught I was. And you acted as if you didn’t care. You never even offered to take bub with you that night, so I could process what had just happened. You left me. You gave bub a hug, gave me one last hug and kiss. And you were gone.
How?
How could you do this to our family. You left me in the dark. It’s been 2 months and I still feel like I am in the dark. I have gotten no real answers from you. Even though I know that you know what really happened. Because I am clueless. You can’t just wake up one day and say that you aren’t happy anymore without reason. You never tried to talk to me about anything. You never even gave me or us a chance to fix whatever was wrong. You just left.
How?
How do you sleep at night, knowing how broken you have left things? How do you go from seeing your son every single day from the day he was born, to hardly at all? How does any of this sit right with you? Because it sure doesn’t sit right with me. And I try. I try my hardest. I invite you to things for him. I ask you if you want to come see him or get him on your days that we have agreed on. And even though you do see him. You aren’t here like you should be. And now I am left at this house that we use to call ours, and get to hear our 2 year old son asking for daddy. Not just once, but a million times a day. And my heart breaks into a million pieces.
I sit and I hold him at night, and I sometimes cry myself to sleep. I kiss his little head and I cry and I apologize to him over and over for things not being the same. I apologize to our son. For you leaving.
How?
How do I cope? How am I suppose to do this without you? How am I suppose to move forward with my life when I seen my entire future in your eyes. And now you’re gone?
Just how?