<human>: Condense the text into a few key points

My girlfriend and I have been dating for over 3 years and are high school sweet hearts. We've had feelings for each other on and off since we were 12 and went through high school together.

Majority of our relationship has always been relatively positive, filled with joy and we rarely ever fight. Yet in the past few months our love has started to slowly wither. 

The other night we had our biggest argument and came close to a breakup. She revealed that she was missing an emotional aspect in our relationship and that she wanted time apart and came out with her bi-sexuality. I can see that there is some emotional connection missing and am willing to work on it.

Throughout my time knowing I have always questioned her  sexuality and in a way knew of all this. After hours of discussion we agreed to open up our relationship. 

Being the egomaniac that I am,  I laid down the rule that she cannot have sex with other men as long as we are together. I was surprised to hear from her that she is not interested in other men. So this works to both of our advantages. 

And as for sex with other women.. We agreed to it only if we BOTH consent. I've told her that I do not plan to have sex with other women as of this moment only  if to my fantasy it is in the form of a threesome.

We both agreed that WE BOTH want each other in our futures, where we can have typical couple things together.. e.g a house, kids, business, travel.

Am i making  a huge mistake here by opening our relationship?? What should I be weary of? Or should I just completely let myself become comfortable with this? What are your thoughts?
<bot>: 3y MF high school sweetheart relationship; F comes out as bisexual and wants to meet other women. M agrees to open up relationship but am feeling unsure about things and would like your thoughts.