I hope it's no one in the current cast who got with Gillian. The world seems small enough as it is, like there's only been 10 people in the town for years, who randomly keep banging friends of friends by coincidence, yet strangely haven't met MC up till recently. I understand the "red string" cop-out, but without some extra supernatural force, the game turning into pure science fiction, it's just far too silly. It would be poor writing, imo. The relationship coincidences are already at a point far past plausibility.