Before we start off on the wrong foot, let's just make it clear that we don't mean someone who will be like our dad. Nobody is looking for a strict protector, but a certain sense of protectiveness does go a long way. It shows you care about your partner and are dedicated to looking after the relationship. Your woman can make her own decisions but knowing you're there in case they go wrong is an extra comfort.
Trust your partner to fend off unwanted male attention in the club. If you have a sense of protectiveness she'll know she can signal you for help if she really needs it. It's all about caring but also knowing when to take a step back and let her handle things. If you can balance these things it will make you super attractive to women.