In a relationship, your significant other should be put before you, but not above you.
Both parties of the relationship should be doing this to contribute to the well-being of the relationship. This ensures that no one is putting more or less into the relationship than the other person. Also, by not putting your SO above you, you avoid the pathetic simpery of many relationships. If you don't understand what that means, all I'm saying is that you should consider all things relationship wise with your SO in mind, but don't let them be the be-all and end-all of your relationship. Don't let them control you. That's also how you stop them from fukking up all of your friendships.
Some of you, unsurprisingly, sound very selfish. If you don't want to put your woman first in the relationship then don't get into a relationship with her. You couldn't possibly satisfy her real needs. Likewise ladies if your man isn't your first priority then don't waste his time. You won't give him what he needs.
With that being said, friends come and go, but your girl is going to be a lot more than a friend to you fellas. Don't try drop your friends, but consider your woman before you do your friends. That's why it's so important to keep your SO locked down before you worry about your friends. When your friends move on in life (and trust me, they will), the only one who will still be around is your SO. Know that.