@rightway2truth I think some of the advice you're getting here is pushing you into kind of a toxic mindset about how you're approaching this.
Bottom line: be collaborative when you negotiate, not combative. Listen to each other's needs and desires and put together terms from there that suit both of you.
Your CTO doesn't sound particularly unreasonable here. First off, you're just getting off the ground and you don't actually need a CTO for your first six months; just having him around advising you (which it sounds like he's offered to do for free) is probably all you need initially.
It's quite common to have a contractor build out your prototype so that you can validate the business and then bring in full time people, and although it will cost you some money, I think that constraint of having to pay that contracted dev for every hour of their time will be helpful to you and force you to prioritize specifically what matters. If you're working with another cofounder and it's just the two of you it's easy to fall into the trap of throwing all the hours of your day at problems without thinking about what's important and that leads to burnout and bad prioritization.
I do agree that your CTO's 50% equity ask is pretty high considering that you're the one putting up your own money. But that's the number you two can negotiate on pretty easily and I think it's easy for you to make your case that his stake should be smaller. But don't ask yourself how little you can get away with offering him, ask yourself how much you can offer him and still feel comfortable. If I have 2% equity and you have 98% equity then I'm not going to be as invested in your company's success as you are.
But importantly, you can't let yourself get personally offended that your cofounder is trying to manage risk. It's good to have a mixture of someone who is taking a leap of faith and someone who is more grounded so that you can really talk things out and make better decisions.
One last thing: I'm not sure about whether your cofounder can pay you money in exchange for his equity stake. But I think that you can probably make some sort of arrangement where costs shift more to him when he comes on so that you can get a little breathing room.