I was not seeking opionions on how is makes parents feel. My question was about if this is a normal process for children, and what my children are going through when are like this. My children are my only concern and responsibility here. I do whatever is good for them.
A related discussion,
11 year old son was started.
It's actually better that they not be calling. There is no need, particularly at their age. The calling probably meets your needs more than it does theirs. The major task that children face when their parents are not together is to adapt to life in two separate households. By using the term 'compartmentalize', you implicitly criticize what they're doing - it's just a matter of acclimating to two different family settings, and that's OK. Allow them to have their time with their father without contact with you.
I would be happy that your kids are having a good time! As long as you have a great relationship with them during YOUR time, let your ex have his time uninterupted. I know that is hard but imagine how he feels too. He once had access to them 24/7 and now is limited to 2 weekends and Wednesday nights. And it seems as if he is a good father and exercises those visitation rights as he is allowed. Imagine how it must feel for him to have his limited time interupted by phone calls to/from you. Again, I know that will be hard to do, but just let the children know that they can call you whenever/if ever they want and cherish your time with them when you have them. Let them have the space to need Mommy on their own terms!! :)