<human>: Bit of background, new boss started a few months back. Get on fairly well with her since she started. Go for coffee, grab lunch and normal office chit chat. 

Was sent by the company on site to a customer in a different timezone for a few months. Went for drinks before leaving with colleagues. Was towards the end of the nights when she got a bit handsie under the table. Brushed it off and went on obliviously for the few months I was away. Chatted to her regularly as she asked for updates on how I was getting on while away.

Got back to the office after a few months away and we continued on as before. Honestly didn't see any different in the relationship outside of just being work colleagues. She's married, I have a GF of 4 years so at no point was I looking beyond being on good terms with my boss. Didn't occur to me at the time some of the subtle hints she was giving off until the "incident".

Long story short, work conference comes up. Put up in a Hotel for the weekend. Ended up chatting to her in the bar about her relationship with her husband which appears to be going through a bit of a rough patch at the moment. Fast forward a couple of hours and a dozen or so drinks later and we ended up all over each other. 

Its been eating me up since it happened. I should have called a halt to it straight away ... but I didn't. 

Ive been suffering from anxiety attacks since it happened. Work has become something I dread walking into. Relationship with my GF has suffered big time. At the cost of a moment of madness, I feel that it will end the best four years of my life with my GF and my career in the company.

Should I just be honest with the gf and find a new job? Only way I can see myself rectifying this situation... Any advice welcome.

Can you condense the text into three sentences or less?
<bot>: One thing lead to another, got it on with my boss at a conference. She's married, I am in a relationship. Should I be honest at the cost of my personal relationship and career?