Some interesting points, thanks everyone!
Onyx, I'm not sure I'm after a FWB...I would love to have a deep meaningful relationship with someone, just without all the expectations that seem to come with the traditional set up. I don't even know how to properly explain it 
Loving, yes. I want to be feel able to engage with people without having to explain myself, or god forbid have to ask permission to have certain friends. I agree about your desire to have someone spend time with you because they genuinely wanted to and not to fulfill an agreement.
Nicky, thanks for the link...will have a read once the kids are in bed! Yes, maybe an open relationship...I have thought about your question (the sex "ownership" thing) a lot over the years and I think I would be ok with a SO sleeping with other people. I even told my ex that I had no issue with him sleeping with other people as long as he used condoms and didn't tell me. I was deeply in love with him at the time so I don't think it was a "flaw" in our relationship. I think I just have more elastic views of sex than some other people!
SGB, it's interesting to realise that this is probably an important part of who I am. I am a little turned off by the idea of swinging clubs, they seem to have such a seedy rep but I am open to exploring the idea. I guess I have this image that they are full of other peoples' husbands trying to pull a fast one! Will start googling :)
Garlic, Your post made me giggle, because I'm hardly buckling under the weight of prospective lovers atm, but I suppose I would go into any new involvement with the premise that I am not monogamous. Love the idea that I could be juggling FWBs! Totally get you on the not living together thing, I think seperate houses but nearby would be perfect if I ever met someone I wanted to get involved with.
Nacster, I love that your FWB has developed on its own despite your original non-monogamy :)
Cogito, I think you've put into words what I was trying to but couldn't...yes, that's it in a nutshell I think.
It's not just about sex, it's about finding a way to explore myself as I grow and change without being held back. (I'm not suggesting that's how all monogamous relationships are, just how I would feel in one).
So, I either need to find a FWB, or a swinger or start a new hobby which is male dominant 