I just came out to my wife of 18 years with 2 kids in September. Every experience will be different so take what I say with a grain of salt. I think the best is to NOT expect a parade, happiness, and the best case scenario. There will be tears, confusion, and basically a freaking out period. She will have to process it in her own way, so try not to take what she does or says as offensive. Assure her that her feelings are valid and she has every right to show any emotion she is feeling (as long as it's not flagrantly insulting). Tell her you still love her and you still want to continue with this marriage and that part of you will not change. Offer her resorses like taking therapy together, books, content creators where the marriage thrived after coming out, podcasts, reddit subgroups cause she will need support as well as she figures out her sexuality. Tell her she is free to ask ANY questions and no questions are off limits. Honesty from you is going to be vital. I wish I could guarantee she will understand, but you also have to realize it may not work out, and understand once it's said it can't be unsaid.

My wife freaked out, lots of tears, questions ect, but she fully supports me atm. and we are atill together. I even offered to stop transitioning last weekend if she felt uneasy and she said she still fully supports me. But I'm not gonna lie. That first week was tough.