Your situation is very similar to mine. The distance between the infidels and the separation etc.
You have received good advice in the Just Found Out Forum. Read the links WAT gave you, he is an excellent tactician and an authority on exposure. I waited months to expose, thought I could fix it myself with care, logic and rational thinking.
I laugh at myself and how naive I was. Then I found this site.
I like the exposure in concentric circle idea. First, without telling your H, call and tell the OW's H. Have all your facts and evidence in front of you and be prepared for anger and denial. Tell him you want to save the marriage and you love your husband. If he is receptive, direct him here. Tell him to get a copy of SAA or send one to him as I did to OMW. (She doesn't want to discuss it further with me, oh, well)
Try to keep your emotions in check, just tell him what you know as opposed to what you think you know. Try to create an atmosphere where he feels he can confide in you and call you back.
Sometimes the above is all it takes. If not, your H's family, your family, friends etc. Anyone that has influence over your H.
Some here will take the scorched earth approach, tell everyone all at once. It has it's place too, your call.
This is likely temporary, 3-hrs away children etc. The hassles of making that work and the financial implications are daunting.
Start to research your options financially/legally. Your H is going to have to think about what this will cost him sooner or later, educate yourself in this regard so you don’t end up in a financial situation he controls. He needs to feel the consequences.
I wish someone had told me this 7 mos. ago.
Good luck.