Hopefully the repercussion is that Shep can't get away with two-timing, is confronted and has to make a choice. Although the chance that the whole thing might blow up in his face and Shep looses both love interests is worrisome. When I made my dude-Shep for my second playthrough/jerk-ass renegade/Tali romance run I went ahead and got with Liara in ME1, knowing full well it will have repercussions. Because hey, why not some drama? Still, I'm contemplating sticking with Tali and only Tali on my third run (go go Vanguard), just to be on the safe side for ME3. On the other hand after a playthough with Dude-Shep, I'm wanting to go back to the superior VA of Fem-Shep. Decisions, decisions.
GAF, I beseech your wisdom!