How do I respectfully tell my wife about um her weight

I love the hell out of my wife. It’s been almost a year and a half since we’ve had our little one. I feel like POS for wanting her to watch her weight but on the other end it is affecting our sex lives (or lack thereof), our marriage to an extent and my mental health.

Being vulnerable here. I think her questionable food habits and lack of interest in exercising is a big factor but she blames it on her genes. She was always a bit over but having two kids has put her body through a lot.

Anyone faced similar situations and navigated successfully together?