Be willing to walk away to gain their respect

So my partner has been repeatedly talking to me with no respect the last few months. Any time I voice my feelings over something he replies to me (if its over text) with a laughing face or will reply LOL and proceed to tell me I’m being silly. He never offers any reassurance, once he told me his ex was more mature than me, he’s called me insane, told me I needed help and generally shrugs off my concerns, with little to no corrective actions to things I say are breaking boundaries.

Every one tells me I need to walk away and mean this, and only once I am really gone, he will gain respect for me. Is this true?

Has anyone ever experienced a case of being treated poorly, gaslighted, spoken to in a general rude manner & left to find they gained the respect?

Do I need to be so drastic to gain respect? Because he generally doesn’t respect me & I am at the point where I am looking to leave him because I can’t handle it. I know when I leave, I have to be ready and able to fully leave him.