OMG. Stop settling for someone who clearly is just stringing you along. His parents. I ask again, have you even met them? You shutting the fvck up will do nothing to make him want to marry you in the future.
"Date and live separately?" You're setting yourself up for a fall. If he wanted to marry you then he'd at least be engaged to you and give you a ring and a time and date five years from now as a wedding date.
Stop being a desperate ninny.
Frankly I think you're his "right now" go to chick and his parents have him lined up to marry someone else when his career has been established.
“The willingness to accept responsibility for one’s own life is the source from which self-respect springs.” ~Joan Didion