Wifes best friend

So this is a true story about the crazy things going on in my life right now. Anyhow. So I was introduced to my wife by a mutual friend. What happened to be her best friend. While dating my wife I always joked and flirted with her best friend who was always single. If there was ever a time she was around an I had my camera out, I would always put it down her shirt or pull her shirt away and take pictures of her cleavage and bras. She always laughed and said that it's to close and they would never turn out... well the cam was always set up properly and they always came out. One day she was giving me a ride home from a party an I had my cam.this time I took it a step further and pulled her shirt up for pics. She fought me but gave up rather easily. This has happened a few times over the years all the while she never said anything to my wife.most recently she has been staying in our spare bedroom living in our house. I occasionally go in the bathroom and take her pics over the shower. She caught me once but never made a big deal. The other night the wife an I were sitting in the hottub and her friend asked to come in. My wife said sure and told her to wear the blue one. I wasn't sure what that meant until she came out wearing my wifes blue bikini. Now her friend is about the same size as her, just doesn't have a belly an her hips are alot wider than my wife's. So after I picked my jaw off the floor I had a really hard time figuring out what was going on. After a while her friend went in to get us more drinks. My wife caught me staring and ask me if I wanted to fuck her? Meaning her friend.... how do you answer that question with the proper answer? After a long silence my wife said it's ok you can. She needs it an I know you want to.... I told her I wasn't sure. After the hot tub my wife must have given her my favorite lingerie that I love my wife in. It has been a few weeks now since that all happened, an since then I have gotten lots of pictures of her friend in many of the same outfits I have of my wife. The next few weeks should be interesting...