Hi. Hope all is well. I'm glad to hear that it was and exciting experience. You said that being with the the guy that your husband introduced you to was the most intense intimate experience of my life. Then being with him and a guy friend of his was and exciting and incredibly overwhelming experience.
I'm no biology person, but if I remember correctly oxytocin is a hormone released during sex that is associated with feeling of bonding and trust. With these intense experiences, that your husband has encouraged you to do, the chemical reaction could literally trigger feelings of bonding. It's possible that while you are in love with your husband, you could start to develop "feelings" for this other man.
Just mentioning it as a possibility that you could develop feelings for this other man. A strong sense of "bonding", but not necessarily "falling in love". The path of this journey can be slippery and is littered with broken relationships and even divorces. I totally understand this has been your husband's idea, that you were initially shocked and dismayed, but he has been urging you to do this.
I see that you now have "stepped away from SW". Hoping that everything is ok, and you are processing it to get your head wrapped around it. Just please be careful. Best wishes 🙏🏻
