What do you mean 'really liked me for a while' and 'take things slow' etc.? Are these things he said? Are you quoting them bc you doubt the truthfulness? Who wanted to take things slowly? What is "a while?"
I actually think it's better if you see multiple people at first. But I don't think you should broadcast or mention it unless directly asked. No one likes hearing that. Everyone prefers to hope they are the only one. Until both people are truly ready to commit, continue to (discreetly) sample as much as you can of what is out there, as long as it doesn't cause you to spread yourself too thin.
But if I find someone I like more than everyone else I'm dealing with, I will want to settle into something with him w/in three months. Everyone is different and some people have more time and patience for playing the field than others. But I, personally, would start to get aggravated if, after three months or so, he still hadn't said or hinted he wanted me to be his.
(Not saying "hinting" is sufficient...but if he hinted, I would open it up for conversation.)