What would be the best route for us to go as a couple?

My fiance is a Canadian citizen while I'm a US citizen, we plan on getting married spiritually rather than legaly to avoid it impacting my disability income, however we also plan on having children soon after we're married. Would he be allowed in the US to help take care of the child, or would he still have to wait till it turns 21? if thats the case what would be the best course of action to take here? if need be we can get properly married, but it riskes me losing my state healthcare which I need to live as I have many health issues that need regular medical care. ideally he would like to work while here as well, he's been working very hard on becoming a teacher and my state is in great need of new teachers, but I'm not sure a high school would got through the effort of a visa for a teacher.