Can't help but wonder if you might be experiencing a lot of hurt and anger at your H and redirecting it at L. After all, it is because of your H that you had to reduce sessions in the first place, if I understand correctly. But maybe it feels safer and more worthwhile to get angry at L for some reason.

I understand not wanting to be "replaced," but I don't think she really has "replaced" you. I hope the session goes well and you get some peace with this.