Can answer the second bit - I have been a little bit envious of people who have someone in their life every now and then.
I usually try to express this in a positive way, such as by saying something like "X is a good guy/girl, I think you make a sweet couple." or "You're really lucky to have someone like X" if it's clear things are going well for them, and I won't cause upset by saying that.
It's sort of nice to turn a rather ugly emotion into something that makes others feel happier in their relationships! Heh.
Hell, I've even talked to guys who have had the confidence to get together with girls I have liked but never made a move towards and congratulated them on their happiness.
It stings a bit at the time, but I think it's better to be gracious like that than be bitter in the long term, it's not like that gets you anywhere other than further isolation.