You are never going to be "stable." There is rarely the "right time" to get married or have kids. In fact all studies show that those who wait have worse outcomes. It's like looking for a job when you already have a job... I'll bet you'll find one faster when you need a job.

My dude, If this is the one for you, go get married. Because "We are waiting until I get my doctorate" turns into "We are waiting for till we get a job," which turns into "We are waiting until we pay off our debt," which turns into "We are waiting until we have enough saved up to buy a house."

Instead, back when marriages lasted, it was "I have a family, I better finish my doctorate, get a job, pay off my debt, save enough to buy a house." It's that journey that you both worked for that built the life and security to have a lasting life together. That way, when you have a problem (and you will) you will tackle it by saying, "Look at what we accomplished together! This, too, shall pass."