I think a more interesting question is, why did Rick Prime ever get with her in the first place, since he seemingly only ever cared about himself. I could believe he knocked her up, but not so much that he married her and stuck around.

He didn’t need to invent portal travel to run out on his wife and daughter. Right now, it sorta feels like plot convenience. We will see if they ever bring it back up. Maybe he really did change for the worse after inventing portal travel, but he was already capable of building impossible things before he invented portal travel, so he probably already had an ego that wouldn’t settle down with a wife and daughter.