"I'm never changing the way I am for anyone." Oh no? Well, then, you've just declared that you'll never grow and that your character and ability to love anyone except yourself will remain forever stunted. Change for the right reasons is good, wise, challenging, and powerful. The trick is knowing how to make healthy changes—what to sacrifice and what to protect—for the sake of more effectively loving God and the people who are important to us.
Close relationships will change us and should change us. Not all change is good change, that is true. But no change at all is the mark of selfishness and immaturity.