eh? come on OP, 'soul mates'- you don't actually know this person, you do know that? you work with them and barely text- what do you know about their real life and their personality. People are very different at work, where they have to be professional, look professional and have to work reasonably hard- doesn't mean they aren't at home behaving like a complete loser. People are attracted to each other all the time OP, it doesn't sound anything particularly out of the ordinary going on here.
WIthout him having said anything to you about his feelings for you, anything you perceive to be between you is quite literally in your mind. Whether it pans out to be something may or may not be the case but there isn't exactly much going on here is there.
I think its no coincedence that this always comes up on here, everyone who is already unhappy in their marriage finds someone representative to latch on to that they think is who they would really want if they were free of their awful marriage. It's 2019 OP, just end your marriage if it's shit, go and date- if you are of the mind you only get one life, i wouldn't go wasting it hopping straight into something with someone else you don't know well outside of work, or you are just going to end up in the same boat in a few years. Leaving a marriage for someone is not the ideal start to a relationship, whatever happy ending stories anyone on here has- he is hardly begging you to end your marriage is he OP, or taking the opportunity after this 'almost' kiss to make his feelings clear.
Leave your DH, then ask him how he feels about you, tell him you think you are soul mates and that you left your DH for him and see what he does. If he is happy to be involved with you while you are with someone, then he's not much of a catch is he..