My partner (F33) and I (M32) went to a play party over the weekend. Our agreement is that we only play together and ask for consent when we involve others.

At the start of the evening, my partner expressed interest in playing with a specific girl. Later in the evening, this girl came up to me while my partner was in the bathroom - I was waiting for her just outside the door. The girl expressed that she wanted to play with us. Everyone had taken MD, and therefore I was feeling very touchy and lovey. I kissed this girl without my partner's consent. My partner came out of the bathroom (without seeing us kiss) and a threesome ensued.

At the end of the night, my partner told me she kissed a girl while at the bar (which I'm fine with). This prompted me to tell her I kissed that girl. She feels extremely upset and betrayed. I completely understand where she's coming from, as I would feel upset if she kissed a guy without my consent, as I perceive them as a threat.

My partner left in the morning, extremely upset and unable to hold eye contact. She says she probably won't ever be able to trust me again. Before this event, she said she has issues trusting people.

I'm giving her space, but it's killing me. She's an amazing person and I'm very worried about losing her. I feel very disappointed in myself for breaking our agreement and am sick with guilt.

Is there anything I can do to regain her trust? Do you have any advice on what I should do with this situation?

Thanks for your help