The detail shots look good, but the shot of the couple needs improvement.
The cause of the problems, is the harsh light that you are shooting in. If you can, it's often helpful to shoot in shade rather than out in the direct sunlight. But if you are going to shoot in the sun, you should think about the light and the shadows. In this case, the brights are very bright and the shadows are rather dark. Also, their position is causing a streak of light to fall across the bride.
Of course, if you expose for the highlights, the shadows will be very dark (and likely the background as well)...but if you expose for the shadows, the brights would even more blown out than they are now.
The solution, if you can't find a better location to shoot) is to add (or subtract) light to the scene. A simple way would be to use flash, which I think you did use...but the problem is that in this scenario, you need a very powerful flash to compete with the bright ambient light.
Another option would be to use a reflector to bounce some light back onto them.
Also, consider the angle at which the sun's light it hitting them. What you have here isn't bad...but because of the strong ratio between the highlights & the shadows, the bright areas cover more of their faces than could have been.
Looking at the scene as a whole, the grass is fairly bright. Brighter than the subjects, which usually isn't what you want. The sky & clouds are also fairly bright.
You could have used a lower exposure setting, to keep the grass & sky under control (and getting deeper color), then use flash or a reflector to light up the subject.
Since you probably can't re-shoot this, I'd suggest burning the background a bit and maybe trying to lighten up the subjects a bit.
Oh ya, I wanted to mention the pose. It feels rather stiff, the groom especially. The bride looks more comfortable. You usually want to avoid shooting people head on, unless you want to emphasize their size. Having them turn a bit, can help to make them look slimmer.