&gt; Now it took a while of convincing and trust building for me to agree

he knew she didn't want to and convinced her to do it, now he's unhappy at the less than perfect threesome that hes been idealising in his head. she was obviously out of her comfort zone, she didn't act how he wanted her to act. people make mistakes, but this never would have happened if he actually gave half a fuck about his girlfriend, her feelings, self-esteem issues/insecurities, etc. and said "you know what i can see that you're not 110% keen on this so lets not have a threesome" 

play stupid games win stupid prizes, such a cliche but so fucking relevant here