I also believe that G and D were a couple for some time in the last years. But I can’t find any reason why the broke up. Do u have a theory?

Yes, I do. The one that comes to my mind most of the time is that one of them wanted to give it real go, go public, move on the same country, live like a regular couple and the other freaked out. I’m still mixed on which one of them wanted it and which one didn’t, but most of the time, i think Gillian freaked out and backtracked. Sometimes, I think David did.
But all in all, I think they’ll try again.