What can I do to be a better girlfriend?

I’ve been with my boyfriend for YEARS I love him so much. I always cry when he says he wants a break or when he tells me I’m being too clingy. But almost every month I see him talking to other girls and I see condom wrappers in the trash can. When I see this stuff I just apologize 😞 because what am I doing wrong? I asked him to marry me twice and he says no. What can I do to be better for him so we can get married? 💔