I 35M caught my wife 40f cheating four years ago and I’m Ok with it

Four years ago, I got off early from work and was driving back home to pick up stuff for gym . As I made my way to my house and my garage door was open and my wife's car and another car were parked there. Didn’t think too much of it at the time I parked over the street and went I entered my house,. The moment I walked in, I could hear the bed in one of our guest bedrooms above me bouncing and rocking as well as very loud moans that was obviously rough sex. I stood in shock and disbelief what I was hearing, but I wasn’t angry if anything I was curious. I slowly and quietly moved up the stairs. I could see from the hall almost from the tops of the stairs I could see my wife bent over doggie style, I watch for what felt like eternity before she was picked up and slammed against the wall being fucked even further. Lots moaning and groaning, lots of loud filthy talk from her and wanting to fucked over and over and I quietly ran out and snuck out to my car, and turned the corner and I watched them leave after almost an hour minutes later However our marriage is great. Like, totally totally great. We have sex constantly, date nights and what have you, we're completely in love. We have twins and our careers and lives are awesome. Over the years, I drive by the house during lunch and the guys car is there couple times a month and I know what is happening and im content with this if my wife finds out I‘m aware, I’ll let her know I’m completely cool with it because our marriage couldn’t be anymore perfect. If this is what she needs to do to keep the marriage stable and keeps herself happy, I'm totally with it. The thing is if she ever figures out I know, I’m gonna tell her that I’m alright with it and she can continue because our marriage is perfect and if she needs this to keep it stable, then I’m all for it.

Edit- kids are mine

-The affair partner is an ex bf of hers from college. I have a friend in the force do a check on his car as well as a mate who is a PI and we checked him out. He’s married with kids. With everything I have checked I can see my marriage is no danger