This is such a longshot... and you'll need background info.
When I was a unsupervised early 70s kid I'd play my parents' LPs and one of the memories I recently thought of was the Val Doonican song "Elusive Butterflies of Love". So start there with your detective work. There was another song in my "play the entire album side" routine that I found slightly ... strange... during these unauthorized music binges. I'm desperate to remember it.
My quick and not complete research into Val's albums doesnt turn up a contender, so I'm thinking him, or Roger Whittaker, or music like that. Glen Campbell? Tom Jones? My parents weren't from the US or really into music so there is a limited roster here.
So, an album from (broadly) 1965-73? Male vocalist, deep, but not ridiculously so, voice. I THINK it is the last track on an otherwise folk/pop album, where everything has been somewhat upbeat on that side but the closer is a lush downer. The lyrics and vibe were, to a child, something maybe you are in your bed and you'll come somewhere with me on a boat/in a dream/in a world and it will be great, but then it's over and back you go and now, morning, you're sad.
This was probably for an adult a deep love song (???)