So here's the deal, my girlfriend of 5 years is going to visit the grave of her  deceased coworker in April, it will be the anniversary of his death. They only worked with each other  for about half a year and she had stopped working with him about 2 months before he tragically died in a car wreck. 
   Now here is why I am jealous, I hardly knew the guy, met him two times, and now I'm finding out that they used to hang out all the time out side of work and talk on the phone every day. I was unaware of this and thought they were just work friends at least that's what it my girlfriend made it seem like. Tonight we went to have some drinks and on the car ride home she confided in me she was worried about going to visit his grave this year because of the nightmares she had the last time. 
  Now I'm not against her going to visit him even though he is buried 4 hours away from our home town but I just don't understand why this guy was so special to her.  We have mutual friends and I've met plenty of her work friends before but it just seems like she was hiding him from me and now she cant get over that he's gone. I confronted her about this and now I'm in the dog house, shes pissed and crying and wont talk to me a out it
  After finding out how close of a relationship they had behind my back even after he is gone, I am still jealous and confused, aita?