I'd like to know if there are couples that are cool with not just riding with but the other type of riding as well as long as there is no hiding the fact.

I voted yes but so far no woman has ridden with me as a duo for a while now so I think I am in the clear or I just am plain fugly.

My wife does not really care. One time because of hotel unavailability/finances her friend who is really good looking and younger and our two sons traveled together for a meet and we stayed in the same hotel room. My wife was more worried that her friend will not get sleep if I snored. Her husband was cool too about it and we are on friendly terms but not buddies per se.

However prolonged hanging out over several times will have a big chance of leading to sexual encounters, however innocent it is to begin with. You just have to be honest with your self if it is leading to that. Usually we deny and before you know it you are doing Kama Sutra experiments. I 'have experience before my marriage and seen it happen more than once at work, with friends and family. I do not want the emotional drain that goes with that anymore.

To the OP unless you are willing to take it further just keep it strictly to cycling and when something innocent as going to a museum or helping out in the local food bank comes up, you know that could mean the beginning of the end.