I've tried to get this a few times. It worked for me when I started a new game and had the lowest scores/lusts/depths. This is just my guess, but "no love interest" probably means you can't have dialogue options that lead to falling in love (and not just not to choose them).

Originally posted by Lord Darth:

I've tried to get this a few times. It worked for me when I started a new game and had the lowest scores/lusts/depths. This is just my guess, but "no love interest" probably means you can't have dialogue options that lead to falling in love (and not just not to choose them).

+1 In my playthrough, I kept the scores below 4, lust levels no greater than 1 and 0 depravity. The achievement popped up after completing the game.

thanks, got it

For me it was enough to have 0 depravity and not telling anyone that I loved them. I had this dialog option available for all characters.

I got it with having a wide range of points with each. Had 3 points lust with Katie. At the end did not tell any I loved them and also did not go for a date with Chandra. Ended up with Sonja ... no divorce

From the offical guide (DLC):
"If you do have a love interest then you will get a different scene for each. With no love interest you will get the “Soy Boy” achievement."

But that did not work for me. In my guide I made a Lone Wolf branch in chapter 12 where I avoided to choose a main love interest. In the end I got the scene with Kleo, which you only get if you have no main love interest, but didn't get the achievement.

I got the achievements "soy boy" in my 1st run, maybe i was lucky and don't know exactly what i did.

I got the achievement by finishing the game with “Chandra and abby” at the same time :) I didn't want to be with Gloria or Ellen. I also got the twins achievement with that same ending, when I told them I was interested in them by talking to Todd in the club.

I don't remember the lust scores but I can share an image if you need one.