tl;dr I’m asking for advice on what to do as I’m falling out of love with my wife whose 6 months pregnant, as I’m having an affair with a colleague

I recently slept with a colleague and friend (f39) following a few dates and a drunken kiss at a work party, a short affair lasting a couple of weeks. She’s currently going through a divorce - from another colleague (m42), also a friend of meine. The affair was short but explosive and I do have some feelings for her. I actually had a crush on her when she first joined our Organization about 5 years ago.

She’s recently told me we have to cool off for now because of the struggle with the divorce process and her (ex) husband and her three kids. The husband also found out about me and her and has not taken it well. It’s exploded at work and he is now taking 2 weeks off to seek professional help. However I can tell that despite this, there are feelings from her towards me and, circumstances aside, we’d be continuing this. We are still messaging a lot.

My wife (f35) and I have been together 10 years and over the last two or three we haven’t been good at all. It’s fizzled out. We were thrilled 5 months ago when she became pregnant, but since then my excitement has gone. I’m spending more time out away from her and not being very supportive. I feel like I have to consciously try to get involved in the pregnancy and excited about things and it doesn’t feel right. I expressed doubts to her recently, about being unsure about living with her. She knows I’m distracted and not in the best place. I’m beginning to regret the baby. As it is, it’s going to be born into an unhappy marriage. I’m beginning to feel as though I’ve made a catastrophic error of judgment, bringing a baby into the world in a relationship i shouldn’t have been in.

I’ve cheated on my wife before, also with a colleague, and that time she found out and was understandably devastated. I simply can’t entertain the idea of her knowing this time.

In short, my actions and thoughts and distractions all point towards me being out of love with my wife during a time that should be precious and happy. I am confused and lost and have no idea what to do, as it slowly dawns on me that we might have made a monumental mistake.