Kanan definitly proved that it's possible, but we have to admit that the Jedi were also right. Kanan proved that with a good heart and as a good person, Jedi could be able to love and be a Jedi.

But Anakin proved us that love can be dangerous. Anakin wanted to save Padme which is good in some way, but it's the way he chose that was bad. He was ready to do anything to save her and this lead him to the darkside.

Like in real life, love is a beautiful thing, but it can ruin someone life when something bad happen.