Bitchy generally refers to someone who is mean or spiteful. More recently, bitchy has been used to describe any woman who isn’t a doormat. If standing up for yourself is bitchy – be bitchy.
I’m not saying that you should be rude, malevolent, or vindictive. That won’t get you where you want to be in your relationship (unless your goal is to alienate your partner and make him leave – then by all means, go right ahead).
Having said that – you should always stand up for what you believe in even within your relationship. You will not be rewarded for subordinating yourself to your partner. You have 50% of the responsibility in a relationship and 100% of the responsibility for your happiness.
Be honest. Be nice. When your needs aren’t being met, communicate them rationally and in a straightforward manner. Men are not good at reading between the lines. If you aren’t clear they will likely think they are doing well while you are growing in your resentment. You can not blame him for not delivering what you need if you never tell him what it is.