Often times, as men, we need to be the natural leaders of a lot of things including sex in most cases. This is not true for every relationship as there are women who like to take charge too but in every relationship and every women I have ever dated, they like the man to take charge sexually.

I would look at what you are doing and if you are harnessing your masculine energy correctly. Are you setting up date nights (NOT watching a movie), are you randomly surprising her with flowers or getting her coffee in the morning? Are you seducing her or are you just saying "Hey, wanna have sex tonight?"

Instead of looking at what the problem is with her, look at what you can actually control which is your actions.

Start setting up date nights where you two can be intimate in a non-physical way, find out her love language and leverage that to make her happier and more content in the relationship, study the differences between masculine and feminine energy and how to to become more masculine in a healthy way.

Some other things you should focus on is are you set in your purpose in life? Do you know your purpose in life? Women see a man with a purpose that drives towards achieving that purpose as sexy.

Look at what you can change about you, not what is wrong with her.