I've had run ins with ghosts, violent ghosts, something other than ghosts that attacked me. And also many orbs. It's been pretty crazy at times. The orbs have always made me feel calm and unthreatened. Whereas with ghosts I tend to feel really sad and/or anxious when they're around as I pick up on their dysfunctional energy. And as I've noted above, some of the unseen things I've had run ins with have attacked me or have done things to scare the crap out of my family. Since you're new to this, here's a quick run down on what I know from experience and what I believe to be true from my own research:
*When you die most people cross over to the other side pretty quick (aka cross over to the light). You go through a process where you convert back to your higher self (pure spirit). As part of that process you become pure love and leave behind anything that we would call negative or threatening. When spirits come to visit us they usually present as orbs. And on a rare occasion will present in their human form that you would remember (usually someone really close to you). But it takes so much energy that this is extremely rare so you're most often going to see the orbs. But they are hard to spot so they may stop by for a visit and you just don't catch them. Some people see orbs when they are thinking of a deceased love one or have some other connection to that person (like celebrating a dead Mother on Mother's Day). Enjoy those times orbs visit as they are all love & have come a very long way to see you.
*Dead people who do not cross into the light remain earth bound ghosts. The reasons they stay run the gambit from guilt over how terrible they were in life, to anger and revenge, to disbelief over a sudden death. Quite a few that stay are mentally ill and are completely confused. Since ghosts are earth bound and are still wanting to stay here they typically present in human form, or a shadow or dark fog or blanket like shape. It varies. Some do seem to be attached to physical objects that once belonged to them. Ghosts are typically the ones that often try to scare you away. Since they are still connected to the earth plane it's easier for ghosts to move things and make noise.
Based on what you've explained, the orb does sound like it could be her ex. But it's really hard to know for sure. You may want to ask if she felt his presence at all or immediately thought of him when that all happened. A lot of very well known mediums who have connected with the other side say that when you take your life you get a do over and get recycled right back as a new born human in pretty short order. But of course no one knows for sure.
I just read an article last night from a psychic who had an abusive former boyfriend who got killed by police. It's a bit of a long read but she explains at the end that she talked to him after death and he was very sorry for the way he had treated her. It's a good read and possibly relates to what you and your girlfriend recently experienced:
You're going to find on all these spiritual sites that opinions of what happens after death and in the spirit world vary. I'm only sharing what I've learned from experiencing things first hand, and from my own research and reading. But it's always good to get a variety of opinions so hopefully others here at EC will jump in for comment.
updated by @hop-daddy: 02/12/20 04:43:16PM