Reposting my reply from another thread, so as not to hijack the OP.

I have been with my partner since we were teenagers (16). He is the only guy I have ever been with. We have two young kids. The last 12-18months have been an incredibly trying time for me personally.

Personally, I think that I lost myself in motherhood…we got stuck in this routine and I think i checked out mentally from family life a long time ago. Even small things seemed unachievable to me. Everything felt like too much effort for too little reward, and I stopped trying. There was no joy in anything I was doing or planning, and no excitement about future plans or options. I began to hate this role, this life…and amongst all of that I acknowledged this thought that I had fallen out of love with my partner. I was incredibly lonely and have very few friends, let alone ones I would consider talking to about this kind of topic.

I turned to the internet to fill that loneliness, chatting online frequently. One person in particular I seemed to click with right away. He lives almost as far away from me as you can get, and we’ve never met, but I have been having an emotional affair with him for months. The whole thing sucks. I feel guilt at home because I just can’t seem to engage in family life. I feel crazy for the way I feel about this person I’ve never even met in real life, and yet can’t seem to stop, don’t want to stop. I really feel like I love him, and not my partner. I too have this sense that I have broken something fundamental. That it can’t be fixed…and I doubt whether I want to fix it. I get lost in scrutinizing everything, feelings, past events, past decisions…I’ve really muddied the waters.

Its like an identity crisis…I feel unhappy with where I am and I looked to the past for explanation. I found fault with so many of my decisions, and managed to color my memories of how things were with the feelings I am currently experiencing. I feel like I have to DO something and figure myself out, and it feels as if to do that I have to reject and break away from the things in my past…and possibly because this link with my partner is part of that…I want that broken too.
I am paralyzed by self-doubt. Sometimes I feel so guilty that I just want to leave. I look at what my behavior puts my partner and my kids through and feel that they would be so much better off without me.