Actually, the original version of "Everlasting Love" was actually by Robert Knight (of "Love On A Mountain Top" fame), not by The Love Affair.
Both versions charted at the same time, but Knight's version languished at the bottom of the Top 50 before disappearing, whereas The Love Affair's version continued to the top.
I recently got hold of an original pressing of the Robert Knight single and my partner and I compared this with an original pressing of the Love Affair single.
If you like nostalgia and energetic, beaty bouncy 60s pop then The Love Affair version wins out.
If you want to know which singer makes the lyrics more believable, then it has to be Robert Knight.
Incidentally, Knight's version eventually made the Top 20 on its re-release in 1974 following the surprise success of "Love On A Mountain Top".
Isn't the world of pop a wonderful thing?
Oh.... and what was the follow-up to "Everlasting Love" for both Robert Knight and The Love Affair?