How can I possibly sleep with everybody?

Obviously it goes without saying that the below post is full of spoilers.

You're not going to be able to sleep with everybody during a single play through, some of the relationships are gender specific and some of them require a lasting relationship through the series in order to romance a particular character in a particular game.

Mass Effect 1

There are four characters to romance in Mass Effect 1:

• Ashley Williams (for male shep)
• Kaiden Alenko (for fem shep)
• Liara T'Soni
• Sha'ira (Asari Consort on board the Citadel)

If the missions on Feros, Noveria, and Virmire are completed before rescuing Liara, a romance between her and Shepard becomes impossible due to the hectic pacing of subsequent events preventing meaningful interactions with each other.

The romance progression for Ashley Williams and Kaiden Alenko starts after the mission on Eden Prime, depending on your characters gender. Either Ashley (if you're male shep) or Kaiden (if you're fem shep) will be at your bedside on the Normandy when you wake up after touching the beacon.

During this phase you must be reassuring to whoever has come to see you. If you're after Liara, ignore this step.

After the first mission has been completed (whichever mission this is) you're given the option to debrief with your crew, starting a conversation with Kaiden or Ashley as required and will give you the option to start a line of questioning that is more intimate.

If you begin to pursue a romance with Liara (after saving her, of course), this will trigger a confrontation with your existing love interest (if you have one) after the next story mission, in which you're asked to choose. If you choose Liara, this will terminate the existing relationship.

On Virmire, you will be asked by Captain Kirrahe split up your team, this choice doesn't matter but the choice at the end of the mission does. Obviously your love interest can't be your love interest as far as the game is concerned if they're dead.

Sha'ira (Asari Consort)

Once on the Citadel, Sha'ira will offer you a mission. Upon completion of the mission, use the conversation options to select dissatisfaction with the reward.

Mass Effect 2

^{These questions contain important information!
How can I control the Romances in Mass Effect 2?
Is it possible to have a romance with all your possibilities in one game?
If I date Liara in ME1, what will affect me if I want to date Tali in ME2 and 3?
Can I cheat on my ME1 sweetheart in ME2 and keep our romance going in ME3?}

Your relationship status from Mass Effect is imported to Mass Effect 2, if you import an existing save. However, it is not possible to romance any of the characters from Mass Effect in Mass Effect 2. You can tell if you have imported a romance as you have a picture of your existing romantic interest in your quarters on the Normandy. If you're unfaithful, this picture is turned face down.

If you're completely faithful, the cutscene on the way to the final mission shows you looking at the picture of your love interest. If not, this cutscene will be a romantic scene between you and your current love interest. Either way, this is imported into Mass Effect 3.

The people available for romancing in Mass Effect 2 are as follows, note that there is an achievement for romancing in Mass Effect 2 called Paramour and if you've imported a romance this will have already been granted.

For male shep:

• Miranda Lawson
• Tali'Zorah vas Neema/vas Normandy
• Jack

For fem shep:

• Jacob Taylor
• Garrrus Vakarian
• Thane Krios

These guys aren't fussed at all, but don't count towards the Paramour achievement and basically fulfill the same role as Sha'ira from Mass Effect but with more conversation options.

• Kelly Chambers
• Samara
• Morinth (basically an instant game over)

Romancing in Mass Effect 2 is based around conversing with your crew members and getting to know them, answering favorably when the opportunities arise. At first there is no gender-unique dialogue when speaking with your crew but over time this changes as you start unlocking the more romantic options. Once these options are available, take them.

Obviously, in order for your love interest to survive into Mass Effect 3, your love interest had to survive the suicide mission at the end of Mass Effect 2. For that matter, so did you.

If you have the Lair of the Shadow Broker DLC, and were in a relationship with Liara in Mass Effect and you haven't cheated on her, you're able to continue your romance with Liara in Mass Effect 2 through this DLC.

Mass Effect 3

^{These questions contain important information!
When does the romance occur?
Who can you romance in Mass Effect 3?
Where's the line between friends and lovers?
Are my romance options in ME3 limited if I cheated on my ME1 romance in ME2?
I'm tired of my lover. How can I break up with them and get a new one?}

The majority of the romantic options available in Mass Effect 3 are imported from the previous games and only available if you're importing an existing romance. These romances are:

• Miranda Lawson
• Tali'Zorah vas Neema/vas Normandy
• Jack
• Garrus Vakarian
• Thane Krios (does not result in Paramour achievement)
• Kelly Chambers

If you had a relationship with Jacob in Mass Effect 2, this is acknowledged in Mass Effect 3 when you meet up with Jacob but he has moved on anyway.

If you're intending to continue a romance with any of the above, ensure that the save you're importing is already romantically involved! Failing that, it is possible to romance the following people from scratch in Mass Effect 3 using similar romance mechanics to Mass Effect 2 with an additional "lock in" mechanic which finalises the relationship. The lock in conversation for each character is relatively obvious, and once complete will change the conversations for all other former and possible love interests.

For male shep:

• Ashley Williams (...and another)
• Steve Cortez

For fem shep:

• Samantha Traynor

For either shep:

• Kaiden Alenko
• Liara T'Soni
• Diana Allers (does not result in Paramour achievement)

With the addition to the Citadel DLC, there are three additional short term romances drunken flings available which do not provide the Paramour achievement:

• Javik (only interested in fem shep)
• James Vega (only interested in fem shep)
• Samara (only if continued from Mass Effect 2)

In order to activate these you must simply be friendly enough, single, and invite them to Citadel: Party. When you wake up in the morning, you will wake up next to one of the above, depending on who is there and who you're most friendly with.

Oh, and if you don't make a move on Tali or Garrus, you get Talibrating.