NE0XY
I see, thank you =)
There is no red on my board,
And there is a PCIe 2.0 slot between the PCIe 3 slots, maybe this makes it so it's extra long or something?

No, I was wrong. There is a PCI 1x slot in between, so you should get the 3 way bridge for your set up. I thought you said rive and missed that it was the black edition, so my apologies for that.
The 2 way long is only 60mm, so it would only extend to the PCI 1x slot after slot 2.
The 3 way is 80 mm, so it will hit slot 1 and 3 on this board, (traditionally slot 4 on most boards, so that was why I was confused) and the Middle set of fingers will sit between the cards.
I am really glad you posted the picture.
This is what I am used to seeing:

I use a 3 way bridge for a 2 card setup between slot 1 and 3 for your board. (1 and 4 on mine)