Firstly, being together for 6 years and having a 2 year old, I'm not surprised you feel less attracted to him. That's totally normal as relationships go on over time and mature from the exciting start to the long haul.
Apart from that, it seems to me like you need to choose between 2 options, but really it's just one choice. Either end the relationship, you'll be single and start following your aspirations / planning an exciting future again, or... stay together and start following your aspirations again.
I'm a similar age to you and my partner is older. Similarly, I had many failed relationships before him and was attracted to his ambition, financial success, etc. Now he seems to have slowed down/run out of steam, so I'm the one going for my career now.
I'm hoping that him seeing me succeed will inspire him too, but if not it doesn't matter because I'm making myself fulfilled living the exciting life/career for myself, which doesn't depend on him. Crucially, this means I no longer feel like I need him to make me feel happy/successful, and this lack of "needing" him in that respect allows me to enjoy everything else he brings to the table.
But if you allow his lack of ambition to be your excuse for not being ambitious yourself this is an error, I think, as you are the only person who can make yourself happy and fulfilled in terms of career.
Does it make sense?