How do you get your other half to take more interest in sex?

I have no complaints really. My girlfriend and I have been together for 5 years with a few stints of making it work long distance - so we've proven our devotion and strength for one another. Love the woman to bits and our sex life fluctuates but is pretty incredible. We are quite content in having sex once or twice a week because our libidos don't demand more.
The problem isn't in the sex either as we have tried new things, keep it loving and intimate and open to new positions, toys etc.

She is open enough to new things and claims that I'm the only guy to have ever made her interested in sex or even enjoy sex ... but...

She never seems to actually talk about sex, talk about her fantasies, or even instigate sex at all besides special occasions.

I'm wondering if this is normal.

I don't feel like I'm demanding or insistent but just to have my partner take an active interest in sex in conversation or pleasure me or instigate sex randomly for fun just seems to be an ever growing desire for me.

I've talked to her openly about this. I ask open questions to try to encourage sexual dialogue. I've suggested new things which we tend to use and then never touch again... it just feels like I'm the only one making an effort or actively thinking about our sex life as an important part of our relationship.

Perhaps Im over thinking or perhaps my libido is becoming out of synch with hers. I just need some general advice on what I could do.

Different people have different libidos. My ex could vary in her comfortableness in sex and dicussing it one week she'd be fine the next incredibly awkard and shy.

It takes patience and time. After having sex ask what went well what didn't. Ask specifics did you like me licking your chest? pulling on your hair? Nibbling your ear? Did you like dirty talk? Did you like me licking your thigh? Reassure her its not weird her likes and dislikes. Follow up and dont be pressured and gradually should renforce comfortable talking. Once I stopped as she didnt seem that into it. After talking it lit a fire into her and we gad great sex.

You say she wont pleasure you or initiate. Do you ever surprise her? Give her head? Orgasm from foreplay without getting something in return? If thats the case she might feel its unfair so doesnt do it.

If shes says nervouse about initiating as not sure it would be good time etc. Try putting two magnets on the fridge one at top other at bottom. You each move your magnet closer to the middle on days you feel receptive. It can be a visual clue that its okay to approach.

Some ladies like my OH for example just dont like to talk about sex. The way she was brought up makes her feel emabarrassed talking about it . Its not an indication that they dont like it either . We get around this be doing a sex survy on each other and then compliling the answers to try new things or not as the case may be. We often do this over a Sunday lunch in the pub .