The Twenties. Sacrifices vs Control

As I get older I learn the difference between making sacrifices and being controlled in a relationship. There seems to be a thin line so I'll try to tackle this subject to the best of my ability. Love can make us cross that line and not even know it. Once it's crossed we allow ourselves to become comfortable and think it's normal because we refer to it as sacrifices, when it's not. For example, let's say I'm dating this amazing person but he has a nasty habit, he's a smoker. Concerned for his health and because there's nothing nastier then kissing a smoker I ask him to stop. From the moment I ask he had the common sense to know it wasn't an ultimatium but a choice. He was willing to make that sacrifice for me so I could be happy in our relationship. When a relationship gets serious you will soon find out there are things that your partner does that you may not always agree with. This does not give anyone an excuse to control anything your partner does. I was with a group of friends one Saturday night and I realized we were missing someone who is usually always in attendance. When I turned to a friend and ask about their whereabouts they replied, "Daniella's boyfriend thinks that we are bad influences on her so can't hang out with us anymore." I was shocked because we've known her for years and became very close friends. It's not like we only go out to bars or clubs but we go camping, bike riding, dinner, movies, etc. Intially my feelings were hurt but my hurt feelings soon turned to anger. I felt like she just removed herself from our lives and didn't think twice about it so in my eyes she was never really my friend. Imagine my surprise when I got a tearful phone call a month later from her. I've never been one to turn away a friend so I stopped everything I was doing and listened to every word. To sum it up, she was a wreck. She missed her friends whom she loved dearly but didn't want to lose the man she has come to love. She didn't know what to do and for the first time I didn't know what to say. She then went on to say that he hated when she hung out late, didn't like her hanging out all the time and dressing so sexy when she went out. I told her there was ways around that to stop hanging out with us shouldn't have been the answer. She said he convinced her with a speech stating sacrifices was sometimes necessary in a relationship. I told her he was absolutely right but he doesn't seem to understand the difference from being controlling to making sacrifices. We hung up and I'm sad to say six months later we no longer hang out and we've been reduced to "facebook" friends. I run into her family and some of her old friends who she no longer keeps contact with. From what I hear her situation has worsened and she is no longer allowed to leave the house unless he is with her and she cannot have company over unless he's home. Sadly in her world this seems perfectly normal. It just goes to show how naive and in love some people can be that they can confuse being controlled is the same as making sacrifices for someone they love.