There is nothing to be worried about if you have provided all the documents requested and the evidence to prove that you are in a genuine relationship. Since it is a little different than a normal sponsorship process yes they do get a little longer, the worst case is that they will ask the applicant to go for an interview to clear some things if they are in doubt. I would suggest you keep collecting your phone call records, emails, skype logs, proof of visits etc and update them before they put your file in the interview queue.