Complicated TY question...

So, my friend came to my wedding with her live-in boyfriend and they gave a gift from both of them.

Since then, they are no longer living together, and have broken up, but may be back together (she's one of those girls who has constant drama in any relationship she's in).

So, now they're kind of on/off. Do I send the TY just to her, or to the both of them?

Thanks!

I would think to whoever you invited to the party, not the guest... unless you are positive he contributed to the gift!