Former New York Yankees star Alex Rodriguez has made his relationship with new girlfriend Meghan Hayden Instagram-official. Hayden, a fitness coach, celebrated Rodriguez’s 51st birthday on Monday by sharing couple photos on her Instagram Story and writing, “Happy Birthday @Arod”, with two red heart emojis. So who is A-Rod’s new girlfriend, Meghan Hayden? Meghan Hayden has her own training platform, Take Off With Meg. Photo: @meghan_hayden_/InstagramMeghan Hayden, 33, is a fitness coach who graduated from the University of Miami with a bachelor’s degree in exercise physiology.