I hated it too, but accepted it as the right thing to do for my DC’s.
I tried to frame it as a positive - ‘who with kids ever gets so much time for themselves’ and ‘one of the bonuses of separated families’.
I did things for me, walking, swimming, coffee out with friends, a theatre trip. My friend, in a similar situation took the opportunity to head off to a festival with her sister.
Time to sit in the garden and read. I cooked well and ate healthily. I liked routine, up early, out for a walk etc.
As life is very busy as a lone parent I also took time to ‘get my house in order’. Decorated, cleaned, shopped ahead before DC’s returned (school uniform, stocked the freezer, booked days out, bought birthday cards/presents ready for the autumn. ) Great to be ahead (for once!).
Anything you like to do, especially things you can’t with a child?