Well, during most of my years of heavy dosing I always tripped with the same crowd of 10-20 guys. We all bonded and became really close during that time. We will always have a special bond and be close friends. And really, anyone I've ever tripped with seemed to become much closer to me afterwards. It's an intensely bonding experience. Although I guess some people are annoying as fuck when they are tripping, so not EVERYONE will share a deep and powerful bond. But it definitely brought me and my friends much closer together.
I had some pretty powerful trips with my various girlfriends and lovers over the years. If your relationship is awesome, it will bring you closer together and take your love to "the next level", but if your relationship is unhealthy, it will just put things under a microscope and you will quickly start to realize that the relationship is doomed.