Most Helpful Guy
His calendar will be stuffed with work + visitation - child support funds, if he's worth his salt. You will have to give more with such a guy than with others.
Once in a long term relationship, be a team player:
.. get the lawyer's visitation schedule
.. create a calendar - per se - with those instructions
.. be the negotiator - if allowed - over trading these days for those days when the surprise calls arrive; know that you can trade up in visitation time when the other side has forgotten to make these courtesy arrangements (used to rolling over him like he doesn't matter) well in advance to an important family function
.. never say negative things about the other side when children are visiting, even if you think they are out of ear shot
.. yes, you can have kids of your own and see them all grow up to be normal siblings loving each other