I think the amount of effort it takes can depend on personality. It doesn't take any physical effort to say something nice as opposed to complain about your partner, but for some people it does take psychological effort particularly if you are already in a downward spiral of disdain.
FMLA-covered establishments
Percent of Establishments 1995 Survey: 10.8%
Percent of Establishments 2000 Survey: 10.8%
Percent of Employees 1995 Survey: 59.5%
Percent of Employees 2000 Survey: 58.3%
Non-covered establishments
Percent of Establishments 1995 Survey: 89.2%
Percent of Establishments 2000 Survey: 89.2%
Percent of Employees 1995 Survey: 40.5%
Percent of Employees 2000 Survey: 41.7%
So, more than 40% of all employees are not covered by FMLA and have no legal right to maternity leave.