Hayden Panettiere is looking back on her 12-year age gap romance with Heroes costar Milo Ventimiglia, revealing that she'd considered marrying him before their breakup. "Every relationship I've ever been in, I invested my whole self in," Panettiere, 36, exclusively tells Us Weekly in this week's cover story while discussing her memoir, This Is Me: A Reckoning, out May 19. "I saw him as my partner and that it was going to hopefully keep going and evolving and lead to marriage.