I like the concept, and I like the short and simple format. I think the poem would be more powerful if you put the last line first and softened the metaphor. 

Ex: 
Without you to hold onto,
I sink into my bed
and drown

Very simplified, ik, but I think it makes it sharper and more painful. Hope you find this constructive :)

I like this poem. It paints a huge picture using a minimum of words. I like how you use the concept of someone drowning without their partner (aka the buoy) to hang onto.  This is a powerful use of metaphor which provides great insight into the depth of the narrator's feelings for his gone partner. Another great thing you did was having the narrator initially saying "our" bed and then correcting themselves to say "my" bed. It shows that the narrator still isn't over the loss of their lover. The title of the poem is also very relevant to the theme and tone of the poem as showing him missing a part of himself without her. Great job!

Short and nice, I like how you correct yourself in the middle symbolizing how used to "our bed" you are.

I really like it. Very relatable to me! Hope this helps!

The last line could simply be "without buoy" as we know that you would've held onto it

I like short and sweet, lost at sea and lost at heart. My only only suggestion would be to trim 'to hold on to' as it's simply fat on the piece - it's already implied that a buoy would keep you afloat. 

Further thoughts: maybe think about changing the title to match the theme of being lost at sea without a buoy to keep you afloat?  :) 

I sink into our bed--

I mean, my bed

and drown

without my buoy to hold on to

https://www.reddit.com/r/OCPoetry/comments/7paqtw/a_stubborn_woman_to_her_long_suffering_man/dsg9ivo/

https://www.reddit.com/r/OCPoetry/comments/7p158e/recovery/dsdvmyo/

Half a man