jealous of the way they kissed not the sex they had, very weirdly specific and I cant explain it

this is gonna be odd. we did a soft swap with another couple last weekend, late 30s, established LS people. the sex part was honestly great and Im not bothered by any of it. like at all. the actual physical stuff she did with my husband, no issue, even kinda hot. what is killing me is the way they kissed. like there was this one moment, must have been 30 seconds long, where they were just kissing slowly on the couch before anything escalated, and his hand was on the side of her face and her eyes were closed and they were doing this thing that I dont know how to describe but it looked... intimate?? in a way that wasnt about sex?? and I felt this hot knife thing in my stomach that I have literally never felt about a sex act. we have a rule about kissing actually, we agreed early in the LS that kissing during play is fine, but I think on some level I assumed kissing meant like "make out heading toward sex" and what I saw was "kissing as the destination, not the road to somewhere". and that broke something. is this a thing?? do other people have a kiss-jealousy that is way bigger than sex-jealousy? do we need to renegotiate the kissing rule even though we already agreed to it? I feel insane for being more jealous of 30 seconds of kissing than of an entire hour of soft swap that came after.