I have been with my girlfriend for 8 years and we have a 2 year old child together. About a year ago, I realised that the relationship was flawed in many ways, mainly that we lack a deep enough connection when we're together - we differ intellectually and just don't laugh together enough. I think I'd just accepted this over the years but it simply became unacceptable to me. I left and shortly afterwards became involved with a colleague who makes me laugh and feel connected in a way that I'd never thought possible. I felt a deeper connection for her than I ever felt towards my partner. This lasted for 2 or 3 months, but the pain of not living with my child became too great and I ended up returning to my girlfriend. My colleague and I remained friends as she understood the situation and could see the pain I was in. Things were fine for about 6 months after - the relationship with my girlfriend even improved. Unfortunately, as time went by, the feeling of discontentment grew and grew and my feelings for my colleague became more significant again. So much so that I am now completely infatuated and regret going back to my girlfriend. The feelings of limerence towards my colleague are completely distracting and not even welcome, but I can't help feeling that I am with the wrong person. My girlfriend is a great mother to my child and is a kind, good person and certainly doesn't deserve the way I am feeling at the moment, even if I can't help it. My colleague isn't seeing anyone else as far as I know and does know how I feel, although she is definitely once bitten, twice shy. Although I think that if I left my girlfriend, things could eventually start up again with my colleague. It just feels like history repeating itself from last year and I don't know what to do. The damage I am causing to everyone, including myself, is significant and I need things to improve quickly. Does anyone have any experience or advice on this?