By Stephanie van den Berg ROTTERDAM (Reuters) – When Ruslan Mykhalchenko leaves his family in the Netherlands to return home to Ukraine next week, one of the things he will miss most is reading his 5-year-old daughter Olivia a bedtime story. It’s a harsh reality for Mykhalchenko and countless Ukrainian fathers who have been separated from their families by the war with Russia, now entering a ninth month. Martial law in Ukraine prevents men aged between 18 and 60 leaving the country. Mykhalchenko, who works with an NGO in Ukraine, was able to snatch some time with his refugee family this week i…