Ideal for me is about 4 inches or 10 cm taller than me. I'm about 5'6"/167 cm, so about 5'10"/177 cm is absolutely perfect for me. In flats he's definitely taller than me, but if I wanna go all supermodel on him I can with some high heels. It's also the perfect difference for leaning in to kiss someone. This is perfect because my boyfriend is exactly 177 cm and I love the difference between us!