We specifically had the discussion in the early stages about involvement with other people, and agreed that we should let eachother know if there was anyone else.
I specifically said that if they were seeing anyone else, I'd like to know so I could determine at that point rather or not I'd like to continue seeing this person. They agreed.
About a year down the road, they got distant and eventually ghosted.
A few weeks later, I learned that the person I'd been seeing for the last year had been involved in an open relationship for the last four years and they are still seeing this person, now.
This was never mentioned to me once, despite being very straight forward about my feelings and multiple conversations specifically pertaining to dating multiple people. They always told me they were single.
I feel like the last year invested into them was a lie and a waste of my time.
I wouldn't judge anyone for living in a way that suits them best, but I feel like I had a right to know so I could make my own decisions pertaining to my level of involvement with this person.
Is it fair to be angry that they never never told me or am I overreacting?