I'm pretty sure I'm the problem in my marriage

I have been with my husband for over 6 years and I'm still terrible at communicating.

When ever we have an argument I kind of just shut down, it's like i can't speak anymore.

I'm also extremely shy around him still, sometimes I hide my face during sex because I'm so embarrased.

I'm also very sensitive and most things make me cry.

Is there anything I can do to change these qualities about myself? Preferably without medication or therapy as we cannot afford anything like that.