We know in starfire the couple split because Thunderwing was going to kill star when he was a yearling but, Silvercloud adopted him when Lightfether died at his birth. That's what split them up.
Still everybody knew that they still loved each other and they still make a great team. When it was star's birthday Thunderwing was about to kill him but there daughter and star's bff morningleaf toke the hit star revived and created river herd and I'm pretty sure that they got back together when the joined star in his new life.
you are? I'm at home
Yes, in Stormbound, she makes it pretty clear they're mates again. I would quote the book, but I don't have it on me right now. (I'm at school)