Just go to an optician and select several pairs of sunglasses and try them on to decide which one suit you best. However, I will give some suggestions. Now, there are many colors available for men, like black, brown, blue and dual-tinted, etc. Then you can choose medium sized lens. Finally choose the glasses frame which suit your face best.
You may go to the brick and mortar store to try the styles or if you want to give him a surprise, you can visit some online stores and most them have try-on system, you can upload a picture of your hubby, and try the frames on to choose the most suitable one. It is decided by his face shape, the color of his skin, the color of his eyes, etc.
There are several tips for men to choose a nice pair of sunglasses this summer. I have several suggestions. In the first place, you should choose some simple-designed sunglasses. The simpleness and conciseness will make you look distinguished and elegant. Secondly, you can choose some bright-colored sport sunglasses. It helps to make you look fashionable and very manly. At last, you can also choose the pilot sunglasses, which are quite fashionable this year. What's more, you should also pay attention to the color and size of your sunglasses when choosing.