<human>: Can you condense the text into three sentences or less?

Before my current boyfriend I had had sex four or five times max with one night stands. So I am completely inexperienced. Not only that, but I don't masturbate or watch porn (I've tried but I don't enjoy it and it doesn't turn me on). In fact I have a pretty low sex drive most of the time.

My boyfriend changed that. I really started to enjoy sex because I loved being with him and having sex with him. 

But he'll casually bring up the fact that I'm bad at sex and this will make me feel super insecure. He'll say things like "why can't you dirty talk?" but I don't know how to dirty talk and it makes me feel awkward. 

He tries to tell me how to improve but it doesn't really help. He'll say move your hips like this or that but no matter what I try it doesn't seem to feel good or have any effect. We have been together for four months now and in the four months of having sex I don't think he believes I have gotten better which is disappointing because I feel like I enjoy it a lot more than at the start and I feel less awkward. 

When he complains I feel like he'll leave me for someone who is better or can satisfy him sexually. I have no clue where to start or how to improve, I always just thought I needed to practice and if I have sex more I'll get better but this hasn't happened. 

At this point I just feel really disappointed that I can't make him happy and that he considers us to have a bad sex life. It's affecting how often I want to have sex and it also makes me feel worse when we do have sex because I worry he didn't enjoy it. What should I do other than magically get better?
<bot>: My boyfriend complains I'm bad at sex, but I don't know how to improve, and it's making me insecure and enjoy sex less/want to have sex less often.