So, I'm in my feels and just need to share.

I (36F) have been polyamorous since my very first relationship at age 17. 8 months ago I started dating a guy (24M) who believes he is very much monogamous. Him being younger and not having had many serious relationships prior, I shared with him my beliefs of polyamory, my reasonings, and my need for it. I explained to him that I was OK with him seeing other women if he felt like he needed to as long as he was honest about it. I believe that if you are dishonest about it, it is cheating. Fast forward a bit and he did end up having sex with another woman. I realized something had happened when there was a condom situation and I confronted him. He lied at first about it but then eventually came clean that, yes, he had sex with another woman. I explained again that it was the lying that was the problem and not the seeing of other women. I forgave him and we continued on. He has discussed it at length with his best friend as well. It was brought up in a discussion between the 3 of us and his friend said to him "the problem isn't seeing other women. Its the not being honest about it." I verbally agreed again. We should all be on the same page by this point. Time passes and he and I break up. About 3 days after the break up he invites me over to snuggle with him and his best friend. We were on good terms so I went and had a nice time snuggling on the couch with the 2 of them. I was saying my goodbyes, purse in hand, heading to the door, and they both started touching me and taking off my clothes. We ended up having a totally awkward and unfulfilling 3some that lasted all of 10 minutes or so. This was my 1st MMF 3some ever and I've been fantasizing about it for as long as I can remember. It was quite disappointing. I got dressed and started to head home. I knew he was planning on seeing another woman that evening, felt complete compersion for him, wished him the best for his date, and left. A few hours later, during casual text conversation, my now ex-bf sends me a time stamped video of him having sex with a another woman during the time we were together. I was shocked. I asked him about it and he tried to convince me it was his ex-gf and that the video was made a long time prior. I confronted him and reminded him that the furniture in the background of the video was newly bought. He then came clean and told me he cheated again...

I do know where I went wrong here. I do know that I should have ended things the first time he cheated. I do know i should have been more realistic, especially with our gap in age. But even so, I can't stop the way it crushes my heart. It is so confusing to me that a partner has the blessing of the other partner to go spend intimate time with other women but just cannot be truthful about it. I've lost my bf, my lover, and my dom in one swoop and I'm just feeling heartbroken over it. I feel so disrespected and sad. I do believe I was honest, open, faithful, and understanding towards him. That does comfort me a little in self, but my heart is still feeling ripped to shreds.

Advice is most welcome but please go easy on me. Thanks for letting me share.