Hi OP. I have created this account just to post on this thread. Please ignore the previous posters who are telling you that you can't be a lesbian, especially as they are basing their 'expertise' on 'having lesbian friends' or being bisexual.
This happened to me when I was 30. I was married but didn't have any children, so it was easier in some ways, but still a horrendous experience. You've been really brave just to admit this to yourself and you're doing all the right things by going to counselling, handling it much better than I did!
It's true that I now couldn't bear the idea of having sex with a man. However, CRUCIALLY, this only became clear to me once I'd admitted my sexuality to myself. I spent years thinking that I just wasn't that into sex or that women didn't enjoy sex as much as men. I didn't have that much experience with men (met my husband at 23 and was v socially awkward throughout school and university, so only had a couple of previous partners). This is obviously linked to the rubbish that society tells women, particularly very young women, about their sexuality and about male sexuality.
I really recommend Alys Fowler's memoir Hidden Nature on this topic, I found it so helpful. What I think she explains so clearly is this isn't just about who you sleep with or fancy, it's about being true to yourself. I'm single at the moment but I'm still SO much happier than when I was dating men.
I am very cross with previous posters who are upsetting you and I won't be returning to this thread as I find it quite upsetting to read as well. However, do not let anyone tell you that you must be bisexual because you've had relationships with men, or because you haven't yet had a relationship with a women. This is rubbish and they don't know what they're talking about.
Sending lots of virtual love and support in this very difficult time 