That's not how it works. The drugs allow you to explore feelings that you're otherwise not able to explore, and work through whatever emotional roadblocks you're having with your partner. Essentially it lets you find the source of your anxiety and problems, when normally you'd just be really anxious and unhappy all the time but you wouldn't know why. And then once you know why you are unhappy it allows you to communicate these feelings with each other so that you can use them to rebuild the relationship. It does also make you love and care much more about the other person's wellbeing, which is an important part of the process, but it's not why it works. The love and empathy part is just what allows you to fix your relationship, it's not actually what fixes it.

"I've never taken LSD but I don't think I would ever want to put myself in the sort of situation that trivializes the death of a child by making it equivalent to downing a pill."

You should take some time to learn about what the experience is actually like. You're trivializing the psychedelic experience by saying that LSD trivializes the death of a child by making it equivalent to downing a pill.