Haven't decided how this would work really. If they end up together again, various things will change:
- Shining's heartless status would be due to Chrysalis nearly draining his of all his love just before Cadence rushes in to save him
- Despite being together, Cadence is unable to forgive Shining for leaving her for so long though she says she understands
- They rarely talk to one another, preferring to use 'their' child, the hybrid, as a messenger.
- Said hybrid would be an innocent party, not understanding why it's parents now act so different and why its mother smells different
- Shining is absent a lot, either drinking or fighting in the war.
- Shining hates Twilight, because she causes his chest to ache due to his heart trying to show its love but not being able to. (Like trying to get water to run through a twisted hose).
And of the things that remain the same:
- Chrysalis is dead, though this time she is killed by a rampaging Cadence who takes years of torment out on her captor.
- Shining can't feel love anymore, thus he comes off as callous and cold, which works for him as a soldier but socially, he's a menace.
- Cadence remains distant with ponies, acting as one of the chief strategist alongside Celestia, since she can't deal with any pony else.
- Cadence doesn't know Twilight personally though she vaguely remembers Shining mentioning her when they were younger.