Relationship problems

For quite sometime now me and my boyfriend have been having issues. We haven’t had sex in over a month now, we barely see each other because we work so often and I’m afraid I’m not attracted to him anymore. We have been together for almost 4 years now and I really don’t want to hurt him by asking for a break. He can be very negative and it just brings me down emotionally. I’m not sure what to do and I’ve been contemplating this for days... how do I tell him? I don’t want to hurt him because I still care.