Should I make a move on the ol ex gf?

Keep it casual, let her know you are open to reuniting, miss her, remember when we did this or that, etc. then let her take the lead. You don't want her current bf kicking you r *** if she's using you to make her bf jealous because they are having some problems. But, if they are having problems and she's having doubts, she could be thinking about what she's missing too. Just let things flow and through actions let her know you still care.

Hhhmm, she's coming over for drinks tomorrow? Is she coming by herself? Well it sounds like she's been dating this guy and maybe the grass wasnt greener on the other side. If you guys get buzzed up together.......you know the odds of you guys flirting or having sex is high. Just go with the flow and she what she says about him. Obviously it couldnt be too great because she wouldnt be coming to your place. Hellooooo!!

No, that's not a good idea. If you are planning on keeping a friendship with her then you could definitely ruin it. It sounds like she kinda wants to make a move on you though, so I would be careful with that especailly since she's in another relationship.

What's the trouble? flirt and tease, she´ll show the road to take

if you don´t want to hurt her just be a gentelman don´t mess up with this girls mind, there´s a reason why she is your ex and there´s a reason why she is now in another relationship.

dont proceed, dont interfere, and dont try anything, remember you guys broke up at one time. that was for a reason

Get her wasted and take advantage of her, she won't remember it anyways