Help merging two repo without connection

Hi, i'm trying to keep synched two repositories without always having a direct connection. My situation is the following: I have a project on my computer with GIT repo. Another developer visited me and cloned my repository connecting the two computer (for example via SSH). Than i sent him for the next days patched of my changes but when he came and we merged i got the following tree:

                                                               /  
-------------------------------------------(my patch)--(my second  
patch)--\
                                                              /                                                                                                                      \
-- (first commit) -- (second  
commit 
)                                                                                                                        (merge 
) --
                                                               
\                                                                                                                      /
                                                               \ (my  
patch)--(my second patch)--------------------------------------------/

I don't thinks its right to have double (or more?) commits. I would have expected something like:

-- (first commit) -- (second commit) -- (my patch)--(my second patch) -- (merge?) --

The patches were created with git-format-patch and merged with git-am. I know that the commits have different sha1 but how can i keep with patches or something similar the two repositories exactly synched?

Thanks

Luca Siciliano