If we go ahead and terminate our relationship, am I entitled to his assets from his career that he developed while we were together?

My boyfriend and I have lived together for 12 1/2 years. We are discussing separating. At one point, I was on his insurance and we sold a house last year with both of our names on it. We have never declared ourselves as married and there is only one occasion where he did not correct someone when they said 'your wife'.