Business partner wants to go his own way – need advice

So, as the title states, my business partner told me the other day that he wants to start his own thing. He's also my good friend.

Necessary background:

This is an online tuition business. I bought into the business about 1.5 yrs ago for £18k. My current business partner had a previous business partner who wanted to leave and I bought half the business from him. The business makes about £15k profit annually before tax. By my calculations, if we discount the amount I spent to buy in, I've made about £1.3k in the 1.5 year period. Essentially, I'm just starting to make money from the investment.

So, my friend/business partner wants to leave as he feels like I'm not putting enough effort into the day to day admin (e.g. replying to clients, tutors etc.). He does admit however that I've changed how the business is actually run for the better (e.g. implementing automated invoicing, sourcing leads through a networking-style method instead of paid ads/solely relying on word of mouth, using software to streamline setting/checking of HW).

He feels like because he brought in most of the clients, he shouldn't have to buy me out but at the same time doesn't want to screw me over as he acknowledges that I put money into buying half of the business. Now, he did bring in most of the clients, but this was over a period of 5 or so years before I joined. Through my methods, I've directly/indirectly brought in 10% of the client base for a negligible cpl (technically zero, the only cost was a small amount of time). Also, I would contend that when I bought into the business, the existing client base was one of the reasons.

The ideal scenario is to sell entirely and we both start fresh, but this is unlikely to happen in the time period that we need it to. Barring this, my preference would be that he buys me out so I can make a clean break.

This is what he proposes:
I plan to still continue tutoring so I should start a new ltd. We then split the client base according to the classes they're in. Likely works out to about 50-50 profit at the start of the academic year, depending on retention. We share the tutors we already have and just hire our own ones as we grow and need more classes. We both still work as teachers, so we would be able to freely advertise the other's business at school with no conflict of interest. Tbf, I move jobs quite often in order to get paid more but he's been at his school for a while so he's more well established, which has the potential to bode well for me. If it wasn't for conflict of interest, we'd have 100s of clients just from his school alone. For the first year, we'd split profits equally and after the first year, we do our own thing. But, this doesn't really address the money I've already put in. Also, he would be keeping the website, branding, google reviews (over 50 reviews, all 5 star) and any other business infrastr

What do you guys think? Are there any better solutions. Feels unfair imo, but I'm too close to look at it objectively. To be clear, I don't mind doing my own thing since I have a lot of ideas for it anyway, but I don't want to come out of this at a loss.

Also, whilst I'm asking about this anyway, settle an argument:

He was looking at making a platform for tutor schedules, HW, feedback etc. so he was using an AI platform to make it. He then asked me to handle hosting, data storage etc since I know more about that stuff. Which to me felt like he was taking the piss. He stated that I could use it for my business anyway so I might as well do it so that I'll be able to easily implement it for myself later. He states that he could do it, but the money for credits/hosting etc would come out of the business account anyway so I'd be paying for it but with no input if he did it. Right now, I've just told him to go ahead and do it how he wants to as long as the cost is manageable since I have my own ideas for doing it differently (and don't really want to share my ideas with a business I'm only temporarily attached to).