How do I catch my cheating partner? My friend has seen him with another woman.

Hello Anu, I want to talk about my something that has been bothering for a long time now. I am 28 years old now. I had immense body image problem as a child because I was often made fun of because of my obesity. With time I became active in school, participating in various events and was good at studies. When I was about 15 years old I started to experience hair loss as well but not too noticeable at the time. After the 1st semester in college I was able to shed excess weight and I started to feel good about how I looked, but the hair loss also continued and my confidence took a massive hit. I also found it quite difficult to commit to a relationship because I was afraid how others would perceive me and I would not be able to handle it. I was not able to keep myself happy so how could I keep someone else happy. Over the years I have kept myself occupied with my job and tried to be as social as I can be, but there has never been a moment where I could just switch off the feeling of being bothered by my hair loss, I did not let go of what I wanted to be, I just wanted to have a time where I would not be made fun of. I was quite sensitive emotionally and this aggravated after hair loss. I always feel that I could not enjoy my teenage life the way I wanted because of something that I don't know how it started. It's frustrating. I feel this huge gap between how am I supposed to be at my current age and what I actually feel as a person right now. Although I have tried to introspect even more this year and tried to accept that I will just have to find a match with what I have, I just don't understand how should I approach this. Sometimes I simulate it as business deal. My hair loss is not really something that a partner may be looking forward to. I still feel like I am not 28 years old. I am not supposed to be like this at 28. I know that there are others out there in the world in my age group who have also experience this, but I feel so isolated here just like how I used to feel as a child when someone would make fun of my weight among a group of kids. What should I do?