<human>: Condense the text into a few key points

My girlfriend and I have been in a happy and loving relationship for two years now; we rarely fight,  communicate well, and to top it off, we have sex nearly daily. Last week, my girlfriend was talking about a thread she was reading on reddit and when I looked over her shoulder, I saw that she had an account. Cool, I thought and we went on with our day.

Well, yesterday I was bored and surfing the web and I happened to remember my girlfriend's account name, so I checked out her profile. I don't think that this is snooping, its a public account that anybody can see, so I don't feel bad. 

Well, what I found was heartbreaking. A recent post from my girlfriend that said (non-verbatim), "I have no sexual desire for my boyfriend, but we still have sex daily because I want him to be happy". Reading through the thread, she states that she is romantically and physically attracted to me, but she feels no desire for sex with me most of the time. She also stated that she doesn't masturbate and it isn't me that is causing her low sex drive, that's just how she always been, also that she orgasms from sex and it's nice, but not necessary. Lastly, she says she loves me and wants to keep me happy and satisfied, so she's willing to sacrifice her lack of want for sex to fulfill me sexually.

I feel like absolute shit. I honestly just don't know what to do. How can I possibly have sex with her knowing that she doesn't really want it or isn't into it? I love this girl more than anything, but I'm so heartbroken. Help!
<bot>: found a recent reddit post from my gf of two years asking for advice about her lot libido, stating that she only has sex with me to keep me happy, but she doesn't have any desire for it.