<human>: I've (21/f) been with my bf (22/m) for 2 years. 

A few weeks ago, he drove me to get a haircut because it's very humid where we live. I told him I wanted a trim so he dropped me off and went shopping. My hair was really long, below my breasts. I got it cut to just below my collar bone. He was surprised but said it looked fine. Well, since then his comments have been making me really self conscious. He just keeps saying how short it is and why I cut it that short. I decided to cut it because it just didn't look good as it was very dry and damaged from the heat. I hate it this short and won't be cutting it again. However, it makes me feel really bad when he says how short it is and that it looked better long. I mean, I agree so I don't know how to reply to these comments. He also keeps asking me why I keep wearing it up in a ponytail and I keep wearing it up because I don't like it and because I don't want him commenting on it. 

I feel like I'm a bad girlfriend because he said how he had this pretty girlfriend with long hair and now I don't have long hair. I tried talking to him about how I felt but I get upset before I actually say anything because this is affecting my self esteem. Any advice?

Can you give me the gist of the text in a nutshell?
<bot>: Boyfriend doesn't like my haircut. It makes me feel bad for cutting it and I don't know how to tell him his comments affect my self esteem.