Help! I've never left a family I was this attached to

I know this is a common anxiety in this community but I would love some support and advice. I've been with this family for nearly two years and we all click SO well. I adore the whole family. The kids adore me too. However, I feel very strongly in my soul that it is time for me to move on to a new position. If you're curious, my last post in this subreddit details my arrangement and the pros and cons of leaving. (I only got one comment and was quite bummed at the lack of engagement actually so hopefully I get more thoughts this time!!) Essentially, I work 4-8, mon-thursday, with no garunteed hours (so give or take 16 hours a week and lots of unpaid vacation weeks). I feel ready to move onto a more typical 9-5 job. It would do wonders for me financially and socially.

I have so much anxiety about breaking the news to this family though. I told them exactly how I was feeling recently and the dad sort of pressured me on the spot to agree to one more year. I know I can't actually do that, the more I think about it, but in the moment I said that was reasonable.

One or both parents are home 85% of the time I am there, so I don't think they will scramble too much. I haven't actually met with any new families yet but I am scheduled to talk to one on the phone this weekend. I should tell them immediately that I am looking for new employment right? Or wait till I've secured something? How do I responsibly detach from the kids?

Thank you so much for any advice.