Fairy tail has the largest number of high quality hetero couples in all of shonens (and all of anime I've seen by far)
The anime has many problems but unlike many other shonens it has one major strength: awesome female characters, and lots of them. And they are written with such love they actually have a lot of chemistry with each other both romantically (I will make a separate post about yaoi and yuri ships from there someday even though none of them are canon) and platonically (also probably coming soon).
It's a rare case of a man and a woman being in love not just because they are a man and a woman and not because they need to be in love, but they are genuinely special for each other and their relationship changes alongside epic magical quests and there are so many of them.
Honestly I know many people think this anime is slop and I agree on their reasoning but I love it dearly and could (abd probably will) talk about it a lot more
I genuinely have never seen the anime with so many good het couples, if you do, let me know