I think you need to sit down and make a list of each of your contributions, and how valuable they are, then attempt to have a serious conversation about how you

I think you need to sit down and make a list of each of your contributions, and how valuable they are, then attempt to have a serious conversation about how your start-up is going, and whether your partnership is the right one to take it forwards. It might be you need a third person to bring balance between you, or it might be that things are going fine and you're being stressed out over very little. Having said that, family is more important than money or material success to many people (including myself), so if you say to him "It's your family or this startup, your choice", be prepared for them to walk away.