u/Flimflamsyd

Today just discovered my wife’s been having an affair. From what I know it’s been going on since last year. She doesn’t know Im aware.
I’m usually head strong but this discovery has blindsided me.
We have 3 children and an active sex life. We are much closer in our marriage than we were few years back. I don’t know what to do. For now, I’ll be keeping quiet and continue as normal so I can gather my thoughts and respond accordingly. We’ve been together almost 20 years since our teens so unsure how I feel throwing it all away. Any advice would be appreciated.