Cheated because of stress.

Married almost 19yrs. I make my living as a local truck driver. Long hours and stress. The confusing part of my story is my wife knows i am bi and used to go on sex dates with other men. Its been about 5yrs since i had sex with another man. But that day i had to work a little over 16hrs. Average 50-70hrs a week. Yes i was chatting with him online and never had time to meet. That night i got off after midnight and he just happened to be online. My wife was sleeping and me and him met at a local park. It was like something else took over. I drove there and he was parked there waiting on me. No one else there i took off my clothes got in his car and he was a black married man. No condom i gave him oral then turned around between his seats and had anal sex. My life is work home work home and i love my wife and my marriage but i felt at the time i needed it. But not sure if it is me getting older or my body was letting the stress out but during the sex i had an explosive orgasm. 1st time. He got close and i just let him finish in me. After neither of us said a word. I was calm. I used a towel to wipe out and got out of his car then he left. Been trying to forgive myself over it. No not telling my wife and have had 3 blood tests so far and negative for stds. Why i hide it i am unsure. My wife was always supportive with that part of me. Yes i could tell her about these desires that have come up again but its been 5yrs since. And that was me meeting a man in a motel i had sex and come home and told her what we did and had more sex. I know i will get horrible comments but i do regret doing it and don't want to do it again.