If she really loved her husband, she would have given the quilt to him to use.
If you feel like you would really like to make him his own quilt, use the same fabric you used for the first one but make the binding a different color. For some reason, I think it would be better to make the quilt in the same colors. If you make different color quilt, she might want to use the new one instead of the one she has...or keep them both.
Regardless, you have no responsililty to make a second quilt to solve their differences. Making a quilt is expensive and takes a lot of time. There is not any way you could have expected this to happen, but I know you feel bad with this scenario even though it had an unexpected consequence.
I feel that you are very concerned with scenario. Sometimes I do things I'd rather not do just to make myself feel better.