To be honest, you should call off your engagement and immediately stop trying to have a child.
If you can't be supportive of a career choice and have doubts now there's fundamental issues at the foundation of your relationship. If you think because of other horror stories that your future is predetermined then that's a massive red flag.
Sure, the schedule sucks. Yes, notable life events will be missed. Though how many jobs could single handidly pay every bill and put your kids through school? Pay for vacations pretty much anywhere? All while allowing you, if you chose, to be a stay at home mother. There's plenty of jobs where sacrifices will be made and your fiance won't make nearly as much. Any job paying six figures or more typically comes with long hours and missed events.
We're talking about 40-60 hours a week as an ATC. That's nothing. I've made relationships work on swing shift putting in 80-100 hours a week for years straight while also balancing being in the guard and leaving.
Being supportive is what good couples do. Relationships get hard. Love never stops, liking does. There could be a month or five years where you don't even like this guy. If you can't stomach the idea of that and working through the hard times no marriage will ever truly last.
I think you should sit down and do some personal reflection as well as talk to your fiance. Explain your concerns to him and maybe even see a counselor. Make sure you two are right for each other. I personally already ended an engagement because she didn't want to support this. It sounds like for you that you may need to reevaluate what marriage means to you. It's not all sunshines and puppies. It's a shit show like anything else at times.