This tv couple is my favourite one. This is the example of two mature people genuinely loving and caring for one another. No pointless drama, no affairs, no selfishness. Sadly, though, the creator has mentioned that they are toxic for each other (Saul is bad for Kim because he makes her do illegal things that she would have never done if it weren’t for his dirty business). And we already know that Kim will probably either leave him, or she will change her persona because of the stuff that she wanted to do to Howard, or maybe she will be imprisoned for the same reason; whatever it is, they are not going to have a happy ending. Still, I believe this couple to be one of the best and I’m glad we have such interesting and strong characters like these two, both together and by themselves.
This song is from The X-Files soundtrack to its second movie. Another series that Vince Gilligan had a hand in and it also had an incredible couple with amazing chemistry: Mulder and Scully! And there's an XF reference in the OP's name!