When I first got my driver's license, I was very cautious on the road. I drove about below the speed limit and never took a right turn on red. I had no problem taking my time when I was going to a fun event, but the following summer, when I started working, I realized that my slow driving meant getting up earlier in the morning to get to work on time. That's how I started going the speed limit, taking right turns on red, and driving like everybody else. I don't do things like learn to drive on the highway because it's what people do - I do things when I want to or have a reason to.
I was used to think that people changed when they entered a relationship, and I knew that I would never do that. But I realize now that there is a difference between changing for someone and changing because of them. Changing for someone means that you're purposely altering yourself to please them. Changing because of someone can mean that the person is your reason for doing something, the same way that sleeping later in the morning is a reason to drive the speed limit to work. I've been wearing more fun outfits since I've had a boyfriend, but I've always liked clothes and putting outfits together. It's just that in recent years, I haven't had anyplace to go and wear fun outfits (I'm not going to dress for a beach party just to sit in a boring class). I haven't changed - I just have a reason to do things that I wanted to do all along.
Like I said in a previous entry, when it comes to acting differently in a relationship, you need to think about how you normally act in other situations. If your behavior varies from situation to situation, if you do things because you have a specific reason, then changing because of another person is no different than learning to drive because you have someplace to go.