Then what the fuck did you wanted? that him to join the Pig and the Rabbit in "ends up alone" group? Yuki had resolution as he moved on ... you might not like the "motherly figure" but it was not as if Yuki did not have reasons to look for a mother figure to start with.
Also when did it blown up in his face? Yuki comes to that conclusion himself, also the manga comes to a resolution to what was the main issue ... the Zodiac Curse,
Comparing Fruits Basket to the standard shounen action series is a disgrace, Fruits Basket ends when the curse is broken and does not continue with a new arc, something shoujo romances tend to do ... something "Lovely Complex" DID in case anyone forgotten Risa's co-worker and its "we can see it were this is going a 20 miles away" arc?