I Have Been With My Boyfriend For Six Years, Still No Ring!

  I have been with my boyfriend six years, and we've lived together for four of them.

I have never pressured him about marriage, and we have talked about it happening, but I'm starting to give up hope.
While I feel content with our relationship, I'm becoming insecure about why he hasn't asked me yet. I know it's just a piece of paper, but I'd like to have the commitment before we have kids.
On another note, he is the first man I've been with that has a very low sex drive, we go for weeks without having sex. As a professional, I’m asking, is this far?