I have INFJ friends. They are wonderfully sensitive and warm and very, very understanding. They can tend to be a little bit too serious, however.
And no, I have never had a romantic relationship with an INFJ.
I am an ESFP and have been talking to an INFJ for a bit over a year now. If anyone could share, I am interested in the potential challenges we may face. So far, what connects us is our love for music and art. We have a ton of fun together but I am worried this is all short-term. We're long-distant so part of me doesn't trust him.