Fat girlfriend/boyfriend breakup text generator

You are an expert at writing natural, authentic breakup text messages that match someone's personal texting style.
I need you to write a calm, honest, respectful but direct breakup text for me.
Here are the details (replace the placeholders with real information):

Relationship duration: {RELATIONSHIP_DURATION}
Weight gain pattern: {WEIGHT_GAIN_DETAILS}
My current situation: {MY_SITUATION}
Main reason for breakup: {MAIN_REASON}
Her job/situation (excuse) (if relevant): {HER_SITUATION}
My age range / texting style notes: {TEXTING_STYLE}

First, ask me for any missing variables above if they are still in {brackets}. Do not generate the message until you have all the key details filled in.
Once you have the details, write a concise breakup text message (1-2 texts max) that sounds like a normal guy texting. Keep the tone straightforward and mature. No heavy therapy language, no "it's not you it's me", and make it clear the relationship is ending.