I wouldn't necessarily say that. It could be a lengthy toxic relationship from there, considering they're going to have to interact at various points for Lily - they can't avoid each other forever, even if they can mostly get around each other with the flexible visiting policy they have at the WUI. Previously, Jake cheated on her, and they separated, having been forced together to get help for Lily, they ended up having their hate fuck. That could absolutely happen again. The whole thing about it is that there's the instant (and potentially violent) regret and self-loathing after the act, which is what we saw with the destruction of the wedding photo. But they still had that connection, it can't be shut off, and sometimes, it can't be ignored.