I’m doing everything I can to help myself, IC, medication, booked a holiday, keeping busy.
I'm so proud of you for that. You really are doing better than you think. Grieving is a process, and it takes time. You're going to feel those losses and some days are just going to be harder than others for awhile.
If you haven't already read it, try The Journey from Abandonment to Healing by Susan Anderson. It's tailor made for your situation and does a really excellent job of explaining the body/brain reaction as well as covering the innate nature of our fear of abandonment. She's got some pretty good tools in her kit to help keep you focused on your recovery too. You might also add Meditation/Mindfulness to your list of therapies. I have trouble doing breathing meditations and get too distracted with whether I'm doing it right, so I would do auditory meditation instead. It sounds like what it is.. pushing everything else aside and listening to all the sounds you can identify for several minutes. Works wonders to put you back in the moment when you've had an unexpected trigger. Four-square breathing can do the same. Emergency responders learn to use it in order to stave off panic. It's just "in-two-three-four, hold-two-three-four, out-two-three-four, hold-two-three-four", and repeat.
One thing which helped me when I was trying to give up rumination was the parable of the Two Wolves:
An old Cherokee is teaching his grandson about life. "A fight is going on inside me," he said to the boy. "It is a terrible fight and it is between two wolves. One is evil – he is anger, envy, sorrow, regret, greed, arrogance, self-pity, guilt, resentment, inferiority, lies, false pride, superiority, and ego."
He continued, "The other is good – he is joy, peace, love, hope, serenity, humility, kindness, benevolence, empathy, generosity, truth, compassion, and faith. The same fight is going on inside you – and inside every other person, too."
The grandson thought about it for a minute and then asked his grandfather, "Which wolf will win?"
The old Cherokee simply replied, "The one you feed."
Our brains are kind of like organic computers and we literally create our neural pathways. Your old programming was a life shared with your cheater and the future you had planned together. You were accustomed to thinking of him in a loving way and believing his rhetoric. Now in the nearer past, you're becoming accustomed to grief and sadness and rumination over what you've lost. So, these are your old wolves, the old neural pathways to which you are accustomed. What you need.. is a new wolf, one of YOUR design, one who is upbeat and has a plan for the future, even if that plan isn't fully formed yet. To all those things you mentioned in the quote box above, you bring your new wolf. You feed that new wolf positive affirmations and optimism, and you starve that old wolf as much as you can. He's not your friend and you shouldn't ever feel sorry for him. He's there to eat your future happiness. I know it sounds kind of silly and a little dissociative, but it really does help.
Anyway, have faith that you're going to be okay. It's going to suck getting there, but you will arrive in the after of it and wonder what you ever saw in that guy. Believe it.