<?php

$dateInterval = new \DateInterval('P1M');

$datePeriod = new \DatePeriod(
    new \DateTimeImmutable('2016-01-01 00:00:00'),
    $dateInterval,
    new \DateTimeImmutable('2016-02-31 00:00:00')
);

echo 'Start: ' . $datePeriod->getStartDate()->format('Y-m-d H:i:s') . PHP_EOL;
echo 'End: ' . $datePeriod->getEndDate()->format('Y-m-d H:i:s') . PHP_EOL;

foreach ($datePeriod as $date)
{
    $dateFrom = $date->format('Y-m-d H:i:s');
    $dateTo = $date->add($dateInterval)->format('Y-m-d H:i:s');

    echo $dateFrom . ' - ' . $dateTo . PHP_EOL;
}