ENFP here. I met an INFJ 2 months ago (we work together). We got on like a house on fire from the second we met, we talk about everything - philosophy, psychology, history, music, travel, MBTI lol... We share the same crazy opinions and theories about the world and other people. Things that, throughout my lifetime, I’ve hardly shared with anyone as most people think I’m a bit crazy/eccentric. I have many friends, but INFJ is the first person I’ve ever met who truly makes me feel like I’m not alone in the world.
The opening paragraph is a common reaction to INFJs. In most cases, it is not reciprocated and it can be a false positive because one of the things we do well is understanding and adapting to the other. We're not being fake. We're sincere, but it doesn't mean there is a genuinely deep connection that goes two-ways. I'm telling you this so you know. In this case, the connection may be mutual.
The rest sounds like the INFJ's marriage is on the rocks.
Mature INFJs tend to be the loyal type and are deeply invested in their partners because they crave deep connection, not surface relationships. Immature/under-developed INFJs may be more devious.
The touching is the obvious behavior. That's flirtation. The rest may or may not have been flirtation, depending on the circumstances. For example, I would
not call an INFJ staring at you a little too long (if you are friends) "flirtation". It could just be communication. Still, people flirt for many reasons that do not mean they actually want to go through with it. So, keep that in mind. It's everything wrapped up together and the vibes you are getting that tell you, and us, that the INFJ is interested.
Going forward....
To get over this crush: Create distance. Interact less. Acknowledge your contribution and change your ways. Encouraging people to talk about themselves creates a bond because people who are talking about themselves feel understood and accepted by the listener. It's a classic technique in dating. Stop doing that. Stop encouraging lengthy texts by texting short, polite replies that are not open-ended and don't encourage the conversation to continue. Don't look at the person who is trying to stare and wink. Move out of 'touching distance". It's fine to be friendly, and be polite, but subtle changes in behavior will give the "not interested" signal. If you get wrapped up in a conversation that is not work related ask about the INFJ's spouse. (Or change the subject.)
Be good to yourself and give yourself other healthy avenues for dopamine rushes, and make sure you care for the inevitable cortisol spike that occurs with heart ache. Find ways to occupy your time. Find avenues through the arts, science, religion, or whatever your interest is, to feel less alone and better understood in this world. When this virus subsides, spend time with other friends, particularly in situations (like parties) where you could meet new people. Ask those new people on dates.