How do I tell my bf I need a break?

Sounds so stupid but how do I tell my boyfriend that I need a break from our relationship? During the time that we break, I’m not going to see anyone else basically just work on myself. I feel like I’m depressed and not happy with myself so it’s causing me to isolate and now I’m kind of falling out of love with him. It’s so hard because I have tried breaking up previously and he won’t let me go. His response to an actual break up was “Baby, I can’t even think about it. Let’s stop talking about it.” And I said “you just don’t want to lose me to which he said, no I do not, no I do not. I can’t lose you.” For a little extra back story, it’s not an “immature love” we have been recently talking about getting married and he also wants to try for a baby