I had the opportunity to get to know a couple and have a nice sexual experience with them a few weeks ago. (I attend a "swingers club" in my area becasuse there isn't a poly community here.) The husband was an Indian guy- sounds a lot like your husband. It was his first time to attend such an event and the first time to have sex with anyone other than his wife. They had an agreement that only if he was comfortable, would anything happen. Let's just say he felt comfortable enough with me! I am quite a bit older than him (at least 15 years) and I was surprized that he was even attracted to me. We did talk some and I guess I put him at ease. His wife was making it "all about him" that night and just wanted to make sure he was comfortable and enjoying himself. We did a lot of dancing and talking and I introduced them to a lot of other people also. She had some fun too, but her main focus was on making sure he was going to have an enjoyable experience.
For the most part, men are men, and they naturally like variety. Even when they don't realize they do....
Maybe you could go out of your way to see if he can feel safe and comfortable enough to experiment some himself.
The key to life is in being fully engaged and peacefully detached simultaneously and authentically in each moment.