I don't think that Willow and Oz would have gone back together if Tara wasn't around either, or maybe they would have for a while but I don't think it would have worked.. I think Willow still would have moved on. And Oz didn't have the wolf under control like he said either which cuold be seen very clear when he found out about Tara, a situation like that could appear even if Tara wasn't there.
