I had Male Shepard romance Liara in ME1. Also chose Kaiden to survive Virmire.
ME2 which was probably the worst way to do this. Oh boy. Slept with Jack after she asked Shepard why he keeps talking to her. Romance Tali before suicide mission then broke up. Hot togther with Miranda.
ME3 I broke up with Miranda then started a romance with Kaiden.
Is this a bad thing to do? I mean it is a role playing game. So why not role play, right?