Tl;dr should I back away from my co worker?

I am a 32m and Im married, we’ve been together 9 years and married for about 3. A year ago I started a new job and I met a co worker(37f, who is also married)and we hit it off. First it was subtle conversation that led to a few lunches with another coworker joining us, to just lunch with just us two. Texts after work hours became frequent and long lunches with ice cream and more personal conversations took place. Spouses come up in our conversations but about 80% in a negative light. I am starting to feel like there are feelings on my end, but not sure if she feels like that about me. My wife met her once and did not seem to care for her very much and I have yet to meet her husband. Which I’m not sure is something she is interested in introducing me to him. We share a lot of laughs and a lot of communication outside of work. Some conversations get generally sexual but nothing direct. She’ll send me pictures of her and her boys and I send her pics of me and my girls. But never include our spouses in pictures we share with each other. We have never done anything physical, although she can be touchy at times. Sometimes we even end the day without a hug. And most nights there is a goodnight text that includes the words “te quiero.” Im not sure if she does it because I do it, but I’m not too sure. Can anybody give me any advice on what I should do? And what in the hell is going on? Is she into me? Should I back off? Thanks in advance.