I need some advice

I am 26M living in Australia and I’m in a bit of a pickle in my marriage. We have been together for 6 years, I got married at 24 to my wife (27F, 25 at the time) after 4 and a half years dating and things were going pretty good overall for a little while. I have a decent paying job even though it sometimes forces us to work opposite schedules but we are fine with that. We have 2 dogs and 2 cats, living in a house we don’t have to pay for, it’s pretty cruisy.

About 6 months ago things started to change. We have had a pretty dead bedroom since then, we have stopped communicating, I feel unsafe sharing my feelings or I feel like I’m always misunderstood or judged for my feelings, and I’m increasingly dreading coming home after work. She watches what I do and what I spend, where I’m going and who I see and questions it constantly. I feel like I’m being watched by the FBI. She has anxiety/depression/ADHD issues and needs constant reassurance that everything is okay which is exhausting. I’m starting to feel like more of a caregiver than a husband.

About four months ago I met someone through my work and begun a short affair. Never slept with her but had kissed and cuddled and other things that didn’t involve sex, but the bulk of the affair was emotional. I felt free and alive, like this was my soulmate, we clicked on literally everything and we had so much more in common than I ever had with my wife. She was everything I ever wanted in once person and I fell in love. It was stupid and selfish and I feel intense shame for it but I couldn’t stop.

Eventually I got found out and after an extremely heated week of fighting and tears, I ended the affair and focused on saving my marriage. I started showing more love to my wife, doing more things that I used to do, generally just trying to be the person that I was when we first started dating.

Except this feels different. It feels more exhausting trying to be the person I was when I was in my early 20s. If anything it feels like I’m growing further and further apart. The small things seem like they’re so much harder than they need to be, I have no interest in sex, we slept on separate couches for a while and it was way more peaceful than any night that we slept in the same bed in recent times. I have tried to have my heart in the right place but I feel like I just can’t get it there anymore without it being an effort.

I still find myself thinking about the other woman and how happy she made me, truthfully the happiest I had felt in years. I feel shame for engaging in the affair and not handling my emotions properly but I want her in my life. I don’t have the energy to make my marriage work anymore. I shouldn’t have made that commitment if I knew I wasn’t going to be ready to honour it for life. I feel like a failure for just wanting to be happy. This woman made me happy and I know she is who I was born to be with.

Feel free to abuse me but I just need some advice on what to do. I don’t want to hurt her but I cannot imagine a happy life living like this forever.