Earth-1.5 became isolated from the rest of the Multiverse after the Crisis
Thus, it wasn't affected by the next inter-dimensional upheavals and wars.Alternatively, and since the Post-Crisis universe also exists...
... then Kara will eventually met her New Earth counterpart in some post-series multiversal adventure.Kal and Kara will eventually heal the rift between them
Now Kara has realized they have been gradually drifting apart, she'll take steps to repair their relationship after her wedding.