You need to know if ...

- Is she still sexually attracted to you?

- Is she enjoying sex with you?

- Does she want to work on this matter with you?

Either it's something, that you both can work on like communications, your bedroom game or something like that, or she just doesn't feel it anymore. Be it hormones or simply falling out of love.

If you don't think, that you can safe this sinking ship, then leave and start a new life. The earlier, the better. It sucks, that you both have a child together, but that's why you have to try everything before pulling the plug. But if nothing helps, the plug it is.

Ending a shitty marriage is only the beginning to a new and better life. For you and her.