You are more then welcome!
I can understand the denial, we've all been there one way or another. But look at it this way; you are only hurting yourself with it, blocking yourself from a much easier and healthier experience. Or think about your travelparty; how would they like to see you struggle versus have a ball being able to invest energy into fun as it's no longer needed (so much) for battling problems without an aid?
With what you are doing; get the rollator! You will find it a world of freedom above anything else. You can sit down whenever you want, don't need to look for an "excuse" to be able to lean, you can transport stuff on/in it safely and not worry about falling while carrying hot coffee for instance. It is ultimate freedom for you to just DO and GO whenever you feel like it. I was the same when needing to get my powerchair (already had a manual chair and
ECV) and have only made things worse for myself then it could've been. My dad actually recently got his own rollator. Still needs some adjusting as he's such a stubborn guy (sjeez, where did I get that from?) but recently you just could see the

happen. He can look forward to going to a mall with my mom instead of worry about distances or use me as an excuse (THE perfect excuse, having a daughter in a wheelchair and thus he always pushed me if I'ld use my manual). It only gives freedom. It's just a tool to enjoy life, nothing more or less.
As far as husbands fears; you can get road rage just walking in the WDW crowds.

Great thing about an ECV is that it has got multiple speed settings, most of them have a turtose and hare button. You can increase speed by pushign the handle more, but when set on turtose it simply can not go full speed. Try one at home a few times. If you do find a rollator is great for smaller and medium distances but a bit "just cutting it" or "just not cutting it" for long distances like a day at WDW, an ECV can be the perfect back up for the rollator. Some training in driving it and esp. being able to do so in small spaces/busy crowds and it is easy. It does take up energy being aware of your surrounding (people will dash in front of you, not being aware that stopping right away is no option with an ECV) but the same goes when using a rollator. You might very well hit somebody while at WDW. And odds are it is not your fault if you are being carefull. People constantly dash in front of others and when using any mobility aid, you can't always prevent a hit from happening. If there is no room to do that, that simply is not your fault but the dashers fault. It's a different thing if you were to aim for legs are not be aware of your surroundings in which case I'ld never advice an ECV. Then again, just a wheelchair or rollator is a weapon also.
Would it help if you rented a rollator first to give it a try at home to go to a mall or something? If you get a taste of the benefits, it might just be the motivation in getting your own happily instead of worrying. Keep in mind though that any rental aid tends to be of a lesser quality because of the amounts of usage and abuse it gets. Also when getting your own, there are more options available to make sure an aid fits your needs AND desires.
It's just a tool to create more freedom. Use it and own it, it can never own or determine you as a person. Have fun with it. Paint it in your favorite colors, decorate it, have some (fake) flowers in the basket, get some flashing light up wheels, do whatever you like to really make it yours. If you need it, you just as well can do it in a way that is you.