Friends with benefits with my coworker?

I’ve been working with this guy for a few months. We are both in our late 20’s and both in 5 year long relationships, which we are both dissatisfied with our sex lives. We recently started having sex about two weeks ago on our lunch break. We sometimes meet up and just drink a beer and talk. But we at least always talk and have a beer before we have any sexual interactions. Since, he does things here and there at work to make my life and job easier. He opens the car door for me when we part ways. He always gives me a goodbye kiss. He has even invited me and my husband on a trip with his girl and their friends. To my understanding, he is not in an open relationship and neither am I. We text off and on all day. Sometimes about sex, sometimes about other things. Is there more to it than just friends with benefits?
Friends with benefits with my coworker?
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