Celes shakes her head firmly, looking back at him then. "I don't blame you. It's not your fault, Locke. That's... that's how Gaia is. It's Garland's fault and we'll make him pay."

What is her fault, however, is getting complacent at all and allowing herself to think that things would never change. That's her problem.

"But there's something I should tell you." Oh goddesses this is hard. "I don't want you to take it the wrong way." That's a great start. "While you were gone... things happened. And I... I've been spending a lot of time with Balthier. We've become... close."

That's one way of saying it. She doesn't want to hurt him... doesn't want to hurt either of them, but she knows Terra's right: either way, one of them will get hurt and there's not much she can do about it.