My girlfriend only wants to sex chat with me than regular chat. What do I do?

My girlfriend stays in a different country. We used to live in the same city, but then fate had took her away from this city to a different country. She never likes to be away from me.

So since I'm a guy who doesn't get to talk to ladies easily I still accepted her as my girlfriend, even when I knew we are having distance relationship.

Well we barely chat with each other because we both are busy with each others work or hanging out with our friends and stuffs. She trusts me blindly and I had done all my best to not break her trust. I love her too and trust her.

Now here comes the issue, she tells me she likes to masturbate thinking about me a lot, which is great, but sometimes she would love me to sex chat her to help her out. I really like to help her, but every time we get to chat she only wants to sex chat with me.

I did tell her about not sex chatting always, but every time she ends up thinking I don't love her when I don't sex chat and only chat.

I'm tired of sex chatting, but that's the only time she chats with me. She tells me she loves to do it in my presence. She is too into masturbation a lot.

What do I do?