In Utah, a member of the military (as defined in state statute) does have a right to not be denied parent-time (Utah appears to be phasing out “visitation”) due to his service. That being said, the terms of the decree control, and must be reviewed in detail.
Best case would be to work through an attorney and attempt an amicable solution -- dad would not loose his parent-time, and the child would not be left with step-mom. The potential of different dates for parent-time could resolve the issue.
Worst case, you might want to file a petition to modify the terms of the decree, to avoid such problems. My reading of the law in Utah is that parent-time (visitation) is time for the parent and child to be together, it is not time to deprive the other parent of time with the child.
Take a copy of your decree to a family law attorney, and explore these options.
Answered on May 13th, 2015 at 1:20 PM