I don't really understand what your plan is? Is it show her this thread and say "See honey, other people are having sex more often."?
Best bet is to talk to her calmly about it. Make it more about her than the fact that you need to have sex more. It could be lots of things:
- Low sex drive
- Anti-depressants or some other libido reducing drugs
- Frequent yeast infections
- You're too big (pat yourself on the back)
- She doesn't get aroused (by you)
At the end of the day, sexual compatibility is very important to a long term relationship. If you guys aren't sexually compatible then it's unlikely to work out long term anyway.