Don't think girlfriend likes sex!

Ah, that can lead to many problems in a relationship. Both of you would have to try and do more for each other. Perhaps you should try and focus more on her pleasure more, rather than having sex maybe you could offer to go down on her or ask her what she would like sexually. Bring up the conversation of sexual fantasies of what you would like to do with each other and see if you can find something she would enjoy. As for her, she needs to understand that you have sexual needs as well and would prefer to have sex with her but she needs to be open to doing more. Both of you need to open up, be honest, and communicate your wants and needs. Sex is a two-way street, you both need to have some enjoyment in it.

Thanks for the advice will do that. Had a little chat with her last night she said that she fantasies about doing lotsa different positions. But wen we do have sex it not like that. I don't unerstand %-) .
Maybe I buy her some romance novels since girls who read them are twice as likely to have sex according to a survey I read.

just try the positions that she wants to try, like in the middle of missionary, change it up.
Do things that interest Her and turn her on.
Do more foreplay because just sex doesn't normally do it for a girl, so maybe it's You that's boring Her and that's why she wants it less often and to just get it over with, you need to make her orgasm and stop focusing on yourself.