This seems a topic better suited to one of the spell sections.
As for the spell itself I personally wouldn't use it for multiple reasons.
I tend not to use the spoken word within spells.
I prefer simple actions or rituals without the use of chant work.
If I were to use chanting I'd use it along with other actions. A candle burning ritual, a sigil working, etc.
I would be entirely put off with the idea of walking up to a couple and pointing at them while saying things.
As well I wouldn't personally care to be on the side of a close significant's anger should they react poorly to my pointing and speaking.
My point is pointing is considered a disrespectful or confrontational act in many countries and areas.
My main reason for not using a spell such as this is if I needed to break a relationship with a significant I'm probably going to do just that. The good old- I don't want to see you anymore.
No spellwork needed. It's direct. It leaves no room for doubt, is clear and letsthe other know how I feel in an honest way without the use of magic.
The example of breaking up a couple as well does not appeal to me. It isn't who I am. Honestly if I like someone, and they prefer someone else I am more liable to simply move on and if I have a friendship with the person I like I am going to leave them alone.
If a friend I like is interested in someone and does not like me the same as I may like them, I'll want them to be happy. They're my friend first and foremost.
If it is someone I don't know well or at all whom I'm attracted to I am especially going to leave their relationship alone.
The spell itself is written fine. It is definitely interesting.
I just personally would rather use a souring spell instead. Less chanting and no need for pointing at people.
It can be cast in the comforts and safety of my home with less chance of confrontation.
Or... write each of their names with their birthday on a piece of paper. Make the papers face each other snd tie them together, but before doing so place black dog hair and black cat hair in between the papers, causing them to fight like cats and dogs. Then bury the pieces of paper.