There are two simple ways to update your sexual repertoire when things start to grow stale. It could just be that you need to switch things up! Yes, even, sex gets boring after a while if you keep having it the same exact way. This doesn't necessarily mean your sex drives are waning, or that you and your partner need to call it quits.
The same might go for doggy style and its many variations. After the thousandth time, missionary position may no longer cut it for you and your partner.