How I overcome with my overthink and jelousy

This all started about a year ago, when my husband joined a music class. He has always loved music, so he wanted to learn more and develop his skills. The class was run by a married couple we already knew.At some point, the husband of the teacher left her. After that, she started talking to my husband more — especially about her marriage problems. My husband was a good listener and very supportive of her during that time.At first, I felt jealous. I told my husband how I was feeling, and he reassured me that he was only trying to help her. He told me not to worry, and I believed him. But even after that conversation, the calls and chats between them didn’t stop. He shared some of their conversations with me, but I started to feel like he wasn’t telling me everything. I couldn’t shake the feeling that something wasn’t right.When I brought it up again, he said he sees her as a sister and doesn’t want to end the friendship. But they were spending a lot of time talking — messaging, calling, sharing photos, and even having long video calls. That made me feel even more uncomfortable and annoyed, and we started fighting about it more often.At first, he used to reassure me. But over time, he stopped engaging in the conversations. Now, whenever I try to express my jealousy or concerns, he becomes silent and avoids the topic.Recently, another male friend joined their circle. The three of them now constantly share their life updates, photos, and personal moments. They talk all the time. When I see my husband with her — even in person — I try to act kind and polite, even though I feel really uncomfortable deep down. I don’t want to embarrass my husband, so I hide how I really feel.The truth is, I feel incredibly lonely. My husband used to be my best friend — the one I could talk to about anything. Now I feel like I don’t have anyone to share my real emotions with. I feel pushed away and disconnected.Because of all our arguments about this, the closeness between us has faded. There’s no intimacy, no emotional connection, and no physical relationship anymore. It feels like there’s a wall between us.I don’t know what to do anymore. I’m hurting deeply, and I feel completely lost.