How does relationships work in mass effect 2?

Okay so I recently got mass effect 2 and I love the game. I know just like the first mass effect you can get into a relationship with one of your crew members but I never completely understood how it worked. Does being male or female decide what crew members you can get into a relationship with or can you get into a relationship with anyone in your crew dispite your gender?How does relationships work in mass effect 2?
Male sheps can have relationships with: Tali, Jack or Miranda, or continue their relationship with Liara*



Female sheps can have relationships with Thane, Garrus or Jacob or continue their relationship with Liara*



* - if you have Lair of the Shadow Broker installed.



Or none of them and keep your ME1 relationships for ME3.



This may explain better: http://masseffect.wikia.com/wiki/RomanceHow does relationships work in mass effect 2?
Your relationship in ME1 carries over in ME2. For example, if you ended up in a relationship with Ashley on ME1, she is still your love interest in ME2. Only thing is, because she isn't a playable character, you don't interact with her. But it still carries on through the game. And if you haven't read up on news about the upcoming Mass Effect 3, they stated that being faithful to that relationship (from ME1) or not carries over to the third game. So, hint hint, if it WAS Ashley you had a relationship with, cheating on her or staying faithful will have its consequences on the third game.



And yes, being male or female decides who you're able to have a romance with

http://masseffect.wikia.com/wiki/Romance#Romance_options_2