ANSWER:

This was not a marriage, rather it was mocking Allah’s rules!! 

Repent sincerely to Allah with deep remorse and exit the group as it’s not permissible to have non mahram men as friends.

Few years ago in a messenger group in the presence of almost 15-20 friends i married a friend.the marriage was just for fun. But i think about it a lot.I am remorseful for my sins and i have repented to Allah.now my question, is my marriage valid? I dont want to take him as my husband. What should i do?