Disrespectful Wife

Right after having sex, my wife and I was talking and got on a topic that caused an argument and out of anger she said " I'm gone find me a man that's gone dick me down right!!" I played it cool and had to go to work shortly after. At work it bothered my mind as to why she would say that to me. So I called her and asked her why did she say that. I asked her was my dick big enough? or was I not pounding her hard enough because she does like it hard. She responded with "I didn't really mean that it's just that your Boring as ****"
I had to get off the phone since I had work to do. The next morning coming home she acted like there was nothing wrong and talked to me normal like we were just going about our day. I don't know what to take from this? A quick history I had cheated on her in the past but haven't in the past 7 years, but I have this feeling no matter how good I am to her or no matter how much I do I get this sinking feeling that she's not 100 percent invested in the marriage. We have been married for 16 years and together for 23 years.