So my fiancee will do anything for love...but he wont do that...

Hes pretty open to most sexual things and is not a germophobe... but he will not drink after me. Straws are ok.. (sometimes) but for some reason actually drinking out of a cup after me freaks him all the way out! Even eating from the same fork does not bother him...Any one else have this issue or any other freak out point when it comes to dealing with people?