as this is a mental health website and I do have mental health issues, the thing that kind of stands out for me is that perhaps this is some impulsivity and hypersexuality things going on with the random sexting? that is an issue I have faced with being bipolar. I don't do a lot of the other things on the bipolar mania list but the hypersexuality and impulsiveness, yes. I'm not so sure I see it as an infidelity problem as much. I have to agree with lolagrace, the potential for harm to you is pretty high by that activity.
however, having had 2 online emotional affairs and one online relationship that moved into real life, I do feel like the emotions were as real as if we were sitting next to one another.
I've had people argue that point but that is just how I feel.
Anyway, I would question the motives behind the sexting or any other sexual activity with multiple people that you engage in outside of your relationships, perhaps with a therapist. the hypersexuality and activities I engaged in were clues that I was suffering bipolar (I ended up at the psychiatrist office to deal with depression over losing the first online bf, when the dr learned of the other behaviors after I had a breakdown is when I was diagnosed with bp)

oh and for the record, no, you are not a horrible person. just human.

I do wish you the best and advise you to please keep yourself safe.