Ray Charles was right: "The night time is the right time to be with the one you love." That's what the speaker of "So We'll Go No More A-Roving" tells us, but he doesn't make it easy for us to figure out just what he means by love. Does he mean the night was made so great that he can't help loving it, or does he mean the night is a time for loving people—for chasing girls, having sex, making love, that sort of thing? It's probably some combination of both. And, by saying he goes roving in the night, and the night was made for love, he's also kind of saying he will love no more. Hmm, why not? Maybe he finally realizes that there are more important things to do.
Sounds weird, but loving can be a bad thing. The speaker still feels it, but he associates it with roving, and hence with something he needs to stop doing.
Love is associated with the night, and with lunacy (literally: moon, or luna, madness). In the first stanza, the speaker mentions love and the moon in the same breath to remind us of that.