<human>: Hi everyone.

So my girlfriend an I have been dating for a reasonably long time considering our age and I'm getting to the point where, for me, the amount of sex we have is frustratingly low. She said she doesn't enjoy it and doesn't want to be something she is forced to do. I understand that so I back off. 

We have sex about once or twice a month. In the first year and a half of our relationship we would do it once or twice a week. 

I try to bring it up that this is something that seriously matters to me but she laughs about it and just does't understand. She says our relationship shouldn't be based off sex and sex shouldn't matter. She also says that sex shouldn't matter in a normal relationship. 

She doesn't think the lack of sex is a reasonable reason to be upset but this is driving me into depression.

How can I explain to her that this is something that matters to me and that this is a perfectly normal thing that I should expect in a relationship?  

**Other info:** She has been on three different types of birth control. After the second time her sex drive noticeably took a hit. And the third time it was better for about a month after switching but declined again. She can't go back to the first one because she would get pretty bad anxiety.

Give me a shortened version of the text
<bot>: How can I explain to her that sex is something that matters to me and that this is a perfectly normal thing that I should expect in a relationship?