i have largely stopped myself recently but still relapse occasionally especially after a few drinks in the evening. I started to fancy her a couple of years ago and had quite innocent conversations and ended up texting occasionally to make usual arrangements and it was just that for over a year or so. I did some obvious flirting even though I knew it was ridiculous and nothing more than a bit of cheeky joking about. I was a bit confused myself when I began to have sexual fantasies about her and thought it a bit ridiculous as I'd never consider there would be any possibility of anything happening between us. Eventually she started flirting back with a naughty look that confirmed she was definitely up for it. My girlfriend never witnessed any of my inappropriate suggestive flirting and I did feel guilty but continued to encourage her mothers attention. One night I got carried away and wrote a pretty smutty text and didn't think I'd actually dare send it as it definitely broke the pretence of merely innocent teasing. Being extremely horny I sent it,that's when things got serious. I had to be extremely careful not to let my partner catch on to my dirty secret but it was also absolutely thrilling to talk dirty to the woman I'd fantasised over. I think we've both become a bit obsessed with each other,we've not had sex but have kissed,I get a pounding boner whenever I see her and now it's very difficult to disguise my obvious lust for her especially because she will deliberately try to tease me and dresses very sexily which I love but it's becoming too much. I know if I cheated I'd be deserving of any contempt I'd get but still can't stop sending her raunchy texts. As long as it stays just flirting between us I don't think it's any real harm and she always replies in kind!