Just really good platonic friends?

My husband and I have been very close friends with another couple for years. We spend holidays together, birthdays together, take vacations together, etc. My husband and the girl are very much like brother and sister and have had this relationship since long before we met. She was the one to set us up actually. Her husband and my husband are friendly, but I would not consider them close friends. However, over the past few years he and I have become very close friends. I still talk to the girl almost daily, but I am now texting the guy almost daily as well. The texts aren't flirty really, but number almost 200 per month back and forth. While our spouses are aware that we have become very close friends and know that we text, I'm not sure they know the amount we text. Are we headed into rocky territory or have I just made a great platonic friend that I should be thankful I have? Even if texts are filled with ual innuendo, is it possible to build ual attraction by the shear number of times we talk throughout the week. It started where we would text once a week or every other week to now we text pretty much daily! I don't think my feelings for him are inappropriate, but I've never had a friend of the opposite that I was this close to. Like I said we have never lied to either of our spouses that we text and talk, but I just don't think they realize exactly how much we do it....and does that even matter?