How to know when to give up?

I’m 26 F thinking about breaking up with my bf 31 Mand need advice. We’ve been together 2 years and we live together. He’s very sensitive and takes things the wrong way which leads to constant arguments. He’s gone through my phone and I’ve lied in the past to avoid his emotional reactions. I feel like I’m on eggshells and I’m not in a mentally safe environment . I don’t fight with anyone else in my life like this but his family and extended family know him to be like this - jokingly saying he’s my problem now. I love him so much and really see my life with him, but now I’m mentally exhausted. Because I’m so young and have my whole life ahead of me I don’t want to enter the rest of my life with someone who doesn’t feel safe when communicating (emotionally safe). I’ve spoken to him previously about this and we discussed him going to therapy because I think there is a deeper rooted issue. IDK 😭 . The highs are amazing, but the lows are too much. How do you know when it’s time to let go? Can people change?

• preface this by saying that he is really wonderful and 80% of the time we are so in love and happy but the 20% is overwhelming.