<human>: Can you succinctly summarize the text in 1-3 sentences?

I am in a serious relationship with my girlfriend, however I met her whilst she was still married, in the middle of her separation with her husband, for which she is still technically married on paper, until things with the papers progress. She stresses that they are no longer together, and are just friends, besides the fact she is with me the whole time - madly in love. The love is real, no doubt about that, and we are happy together.

However last night she left her email inbox open on my laptop, and I couldn't resist looking at some of her emails, some were conversation histories of Google Chat. I started reading some of the conversations between her and her ex-husband. I feel super guilty but I couldn't resist. She is Spanish but I only speak English.

I read stuff like:  
Exhusband: yo tambien, fui lindo tomar una siesta contigo hoy  
GF: fue rico dormir contigo esta tardecita sii lo mismo senti  
Exhusband: gracias por enseñarme a querer de verdad  
GF: ohhhhh gracias a ti mi exhusband por todo lo que me has enseñado  
Exhusband: tu tambien  
GF: yo solo quiero the best for you! the BEST!  

Which according to Google translate means that they slept together either as a nap (i.e. not sexual) or had sex, this was on a date when I was out of the country on business. Is anyone able to translate this properly?
I feel so shit and guilty and really don't want to lose this girl. Should I have not read her messages? What does this mean? :( should I confront her and tell her I read her messages?
<bot>: found chat logs on laptop showing gf talking to ex husband about sleeping together, can someone spanish please help me and explain?