@xeno77 Artificial simply means that it didn't come about naturally, and in this case it's true. They only exist because you're choosing to mess with time. Had you never done that, they'd never exist. So it's pretty right to call them unnatural or artificial, because
you are technically their creator and not a natural flow of events.
You wouldn't exist in the other timeline either, by splitting the timeline you've effectively thrown yourself into a different world and made it impossible to return because any other changes you make only recreates the same problem. The world may have many things similar to the one you came from but will be innately different. For example your girlfriend begins to believe and act out in ways that she normally would never have done if you never split the timeline, she might consider things like living beings to be replaceable, she might become violent because she believes that it can be undone without any real harm. Essentially, by creating the alternate timeline, you
made a version of your girlfriend that's far more outlandishly evil than your original girlfriend would ever be.
To the original timeline, you left and never came back so no big personality changes would likely occur to her.
So you essentially have to live with the knowledge that you're causing your loved ones in the previous timeline suffer and you can't see them again. Even if the people in front of you look like them, they're not them and you'd know that. That weight would carry some level profoundness on your life from then one.