How do you leave a long relationship?

I've been trying with someone for over 5 years. We're still very young, but we've lived together for 4 years. We're technically engaged, even though my half of the family doesnt know (and hasn't since our engagement my senior year in HS).

We do argue a lot, usually about money. We've been through so much together. We nearly broke up last week, and I was finally ready to, but he kept saying things like "I need you" and so on, while I tried to insist leaving would be good for him, since I havent been acting in love with him the right way in weeks. He deserves better. He deserves to be with someone who's in love with him back. But he wants to work on us.

We've been down the almost-breakup road a few times before, usually with me as the "please dont go" person. Now I'm finally ready to move on. Be me. Start fresher. And I kind of have feelings for someone else.

If we break it off, I'd stay in the area we live in now. He'd move and live with a friend (big house). And that's okay with me. I dont hate him. We just both deserve to be happy. Even if it's not with each other.

I've never broken up with someone in person before, really, especially not on good terms. Hes someone I'll always love, but I dont feel in love anymore.

Any advice, or just kind words, or even lectures? I just need to vent and need help.