I think it was during the time magneto pulled the adamantium out of him and Logan was hallucinating Magnetos everywhere making him extra violent and...
CC had actually more than implied Warren and Jean more than once. Once during the Byrne era with Warren saying "looking good red" and she kisses him...
Yes, I remember this and he didn't appear again until years later but Rachel had sacrificed herself by then. I wonder if he would go for her a third...