Hey there Happy Man and welcome to our caring community;
You seem really happy within this union except for sexual connections. Do you identify as gay or bi? (Re 'woman of your dreams' comment) I identify as Bi, been married, divorced and now single.
You seem to have made the decision which is quite an accomplishment; congratulations. Telling your wife is mostly about your sexuality, but it's also about her response.
There's no perfect way to break someone's heart. Nice environment, food and beverages to last what might end up a very long conversation, (no alcohol!) and a comfortable spot without other people would be respectful.
The words though are your main concern yes? IMO, keep it simple. "There's something I need to tell you...I'm gay." That's it in a nutshell ok; the rest is about her. Let her ask questions or make comments. Keep answers short and direct. She'll spot a lie in a heartbeat. Support her if she cries and listen with your tongue between your teeth if you have to.
If there's anger, assist her to let the rage out and stay completely balanced with the sole intent of helping her get thru it. Validate her words with short responses such as; "I know..." or "Yes, I can see what you're saying." Take cutting words with humility...it's all about her. Don't justify anything, just keep her talking.
Please don't make the mistake of saying it breaks your heart at this time as the energy will be turned away from her. Leave that until she's ready to hear it. (Unless she asks what you feel. Again, make it short and sensitive, then turn it back to how she feels)
If you end up at a stage where there's an opportunity to make plans, put it off! Emotions will cause future plans to be based on panic and what-if's. That's another conversation to have at home over a coffee.
My point is, go thru each stage together. You both have issues personally and relevant ones together re care giving of your kids, living arrangements and financial stability.
I wish you luck Man, both of you.
Gentle and kind all the way...hope is eternal.