Answer:
Two horses, swiftest traveling, harnessed in a pair, and grazing ever in places. Distant from them.
He has married many women, but has never been married. Who is he?
It is weightless, you can see it. If you put it in a barrel it will make it lighter?
It doesn't live within a house, nor does it live without. Most will use it when they come in, and again when they go out.
The more of it there is, the less you see.
If itβs information you seek, come and see me. If itβs pairs of letters you need, I have consecutively three. What am I?