I met a man around two years ago. He asked my colleague about me, found me on social media more than a year later, and eventually started messaging me and asked me out.

Our first date was incredible, but something didn’t feel right. I did a little online research (of course) and found that he is with someone else – and that they live together. I did not tell him what I discovered.

We would see each other once a month, and if I asked, he would always say he is single. Last month, I was planning a little road trip to get out of town and relax. He said he wanted to go with me, rented a cozy apartment with a view, and we spent the whole weekend together. It swept me off my feet; no one has ever made me feel so good. Then, when he went on a business trip, he kept texting, telling me how much he missed me.

Weeks later, when I was supposed to go to his place, he told me his brother was visiting, but I saw that his girlfriend was posting Instagram stories from their apartment. I felt it was the moment I should probably tell him that I know the truth, but I couldn’t say a single word. He says he wants to see me more often; he is now planning a trip to Paris for us in a couple of weeks. I can’t help but keep seeing him. I know that the answer is to cut him off, stop seeing him, and move on, but I feel I can’t do this.

– I can’t