I've been with my wife for 12 years and I've never thought of myself as clingy because I told her that I loved, needed, or wanted her. She's your wife, that's exactly how you're supposed to feel.
I'm a little concerned with her responses to you. When my wife and I first embarked on this journey we knew that we had to take things slow and figure things out as they came up. We didn't have sites like this at the time, and really didn't know anything about polyamory. But we knew that WE were going to be together no matter what. So if this was how we were going to live our life, then we needed to make sure that along the way we each were always secure in our feelings for each other.
That meant that if there was a woman that she wasn't comfortable with, then I backed off and my wife and I talked. We talked about why she was uncomfortable. We figured out what the issues were and then figured out what we needed to do to resolve them. It doesn't seem to me that your wife is doing that part very well.
Which brings me to something you said in an earlier post. That you felt in your gut that things were changing. After 13 years I'm sure that there is a reason you're feeling that way. Your wife needs to stop and listen to what you're saying or I'm not sure this is going to work.
Live life to the fullest 'cause you never know if you're gonna wake up tomorrow!