There really is no definitive answer to this question as each situation will be different to the next.
If you have separated amicably then spending time together may not be an issue. Whereas if you’ve had a more acrimonious separation, you may not be suited to spend much time together at all.
This is something that only you will know the answer to. The main thing to keep in mind is the well-being of the children involved and putting their needs above everything else.