You are their parent Excile, not him. He has no rights in respect of your daughters. He may come and go who knows - but you won't.
Do you and your W have specific agreed, written down arrangements WRT time with your children? If not, I think it is imperative to work towards this.
Yes, do make plans for yourself and work on accepting the end of the M - and the friendship you had hoped might lead to more. You can co-operatively coparent of course.
Yes, do reach out to old friends and make plans - but watch out with talking to women due to loneliness. Use the time to heal and work on your own issues would be my advice.
T 13 M 7 Me 48 H 46 SS 15 BD 7.14 PA D final 5.16 (H filed)
We receive & we lose, and must try to achieve gratitude & embrace with whole hearts whatever of life that remains after the losses - Dubus