He wants to turn you into a supportive friend on who he can rely.
Most of the times, he does that because he still cares about this connection and doesn't like the idea of you not being in his life at all.
Do you have to respond to his needs?
Of course not!
You can dissolve a potential freindship by not returning his calls or emails or simply telling him openly that you are no longer there for him.
It is your right!
You owe him nothing!
When he puts you into the friend zone, it can be prety painful to see him date new women.
You don't have to witness that.
Do whatever it takes to put as much distance between you and him as you want.
The relationship is over! You owe him nothing, ok?
Now...
What if you have children, work together or are still sorting out details of a business or assets you have together?
In that case, stick to being diplomatic and respectful.
Yes! If you need to interact with him for whatever reason, cultivate a connection which is based on those qualities.
You realize though that ACTIVELY building a friendship is a totally different story, right?
When you are good friends, you hang out together, you support each other, you invite him to parties, you introduice him to your newtork, etc.
Going that way is ALWAYS an option IF you enjoy it too and you both want it.
Yes, it is possible to turn a past romantic relationship into a solid friendship.
In my experience with coaching women in breakup transitions, having a very active friendship with an ex doesn't happen often.
In most cases, simple, respectful and occasional interactions with an ex will be a much better option and give you more space to rebuild a love life without him.