Yes, Ivanova and Talia Winters were always slated to be a sexually active lesbian couple;

JMS told [Sci-Fi Universe][1] (March 1996)

> "We had it growing since the very first episode of the first season.
> The relationship was about all of that mutual antagonism that really
> means they're attracted."

Andrea Thompson (who played Winters) stated in "[Creating Babylon 5][2]" that: 

> "There was a sexual relationship between Talia and Commander Ivanova.
> It was edited so that it was not blatant. But that was exactly what
> happened. It had been talked about from the very beginning" (The
> Creating of Babylon 5).

An SFX Interview in [July 1997][3] showed that they wanted to explore the relationship further

> "I think that if Andrea Thompson had not left, we would have
> definitely explored the relationship further. That was the intention,
> but because she wanted to get out, we had to wrap it up quickly"

Claudia Christian also made it abundantly clear that her relationship with Talia was based on a **mutual sexual attraction:**

> "I'll be quite honest, I was like the lesbian poster child; I got a
> lot of people writing to me from the armed forces and so forth, who
> loved the fact that they thought I was going to be gay. I'm not gay in
> real life, and I don't think I'm gay on the show, but I definitely
> think she had some kind of thing with Talia. I think a lot of gay
> women were hoping for that, and I didn't want to disappoint them; I
> thought it would be fun... Then Andrea left the show, so that's why it
> never came to fruition. The only reason it didn't go further is
> because we had to get rid of the character because Andrea wanted to
> leave. It could have been a long relationship."
<sub><sup>The Official Babylon 5 Magazine : June 1996</sub></sup>

JMS (on the excellent [Midwinter website][4]) made it clear that they were involved with each other both sexually *and* on an emotional level;

> Susan and Talia had been dancing around one another for months; that
> night [e.g. Divided Loyalties}, though, would've been the first time they got *physically*
> intimate.


  [1]: http://www.amazon.com/BABYLON-BRUCE-BOXLEITNER-UNIVERSE-TRAVOLTA/dp/B002D4LFEQ
  [2]: http://www.amazon.co.uk/Creating-Babylon-5-David-Bassom/dp/0345414527
  [3]: http://www.amazon.co.uk/Sfx-Magazine-No-July-1997/dp/B001M5DX7E
  [4]: http://www.midwinter.com/lurk/guide/041.html#JS