If you happen to be asexual, there's an aromantics subforum on the german branch of AVEN ( https://www.aven-forum.de/viewforum.php?f=36 ). However, even if it is interesting from a scientific perspective to experience aromanticism from another point of view, this is quite toxic for non-asexuals and I personally would not use it as a forum. From a quick google search, the only things I found were asexual related too. I don't know anything about offline groups but I wouldn't be that optimistic judging from the online presence.