I take it you haven't read
this thread? The tl;dr version of it is that someone had asked for a co-writer like you did and some people mention reasons why asking for a co-writer isn't a good idea and it'll be even more work for you to do with instead of writing a story for yourself. Some quick points:
-Clash of different writing styles
-One writer suddenly doing all the work and the other not putting the effort
-Many people here not sure your skill level of writing
-Communication problems
Not trying to burst your bubble or anything, but I think you need to reconsider about asking a collaboration out in the open like that. You might be better off asking someone you know to write with you.