Okay, this was a tough one. Here are my reasons for voting the way I did.

1. When Odo confesses to Arissa that she was his 'first time' and she questions it, Odo explains the link as something she would consider sexual.

2. Every one of Odo's experiences with the Link with another Changeling (with the exception of healing the FF in WYLB), his face is a picture of ecstasy. His is the face of someone who is in the throes of overwhelming physical sensations. Sounds sexual to me.

3. From "The Searach II" Odo is talking to the FF and he tells her his homeworld is different than he imagined. She responds with "Whatever you imagined . . . I promise it will be better." And immediately after that she initiates the Link with Odo. Again, sounds very provocative and sexual to me. Another sexually provocative remark by the FF occurs in "Behind the Lines" when she tries to initiate the Link with Odo (after he admits to her his vulnerability around Kira and how he wished he could tear his feelings for her out of him but can't) and he initially resists. She is holding his arm and she has already shifted. She asks "Do you want me to stop?" That always reminded me of being a teenager in the backseat of your boyfriend's car . . . You know.

4. From "Favor the Bold." After Odo and the FF have sexual intercourse as humanoids, the FF compares the experience unfavorably to the Link. "What they (humanoids) consider intimacy is only a shadow of what we (Changelings) experience in the Link."
This unfavorable comparison is echoed by Laas ("Chimera") when he chides Odo with his "Love conquers all" statement and then follows that up by saying "Compared to the Link it (love) is a pale shadow - a feeble attempt to compensate for the isolation mono-forms feel because they're trapped inside themselves."

5. The expression of dismay and hurt on Kira's face when Odo tells her he Linked with Laas. What makes it worse for her is the way Odo equivocates about the Link, likening it to 'talking' for humanoids. She calls him on that, saying its "a little more . . . personal than talking," and Odo looks a little chagrined as he admits that yes, it is. Kira's subsequent forced levity is an indication of just how uneasy she is.

6. The actors themselves believed they were playing sexual scenes together and portrayed their characters that way.

Having said all that, since it is impossible for Odo and Kira to Link in a way that's natural for changelings, Odo himself may have deluded himself that Linking wasn't sexual in the way his relationship with Kira was. But I think Kira viewed the Link as an intimate act. I also think that at some point Odo realizes that Kira sees his relationship with Laas as an act of adultery and that only adds to his uncertainly about whether she will take him back when he comes to her quarters. He's not only hurt her, he's once again betrayed her, this time in the most devastating way possible for a couple. Thinking about it, it really says something about how deeply Kira loved Odo that she would take him back. I think Kira's unwavering black and white code of ethics would not under normal circumstances make allowances for cheating. Remember her outrage over Jadzia's holosuite program about King Arthur when Kira punched out Lancelot for flirting with her because she was playing a married woman.

Whew. Okay, I'm done.

I thought about this one deeply, since I love both Odo and Kira. And I came to the conclusion that, yes, he did in fact cheat on her.

"Chimera" is the episode where both Odo and Kira come to grips with the one thing they can't give the other: Kira can't link with Odo, and Odo can never give Kira a child. Up until now, those things didn't matter much.

If Kira had slept with a Bajoran man on the grounds that he could give her a child and Odo couldn't, then Odo would feel hurt. He would feel badly that it was something he couldn't do for her, that she wanted. Would that mean Kira had cheated on Odo? Yes. If it's okay for Odo to link with another Changeling while in a manogamous relationship with Kira, then what of Kira? Is she supposed to sit back and say, "Okay, go for it? I'll be waiting at home when you're done linking?" IMO, it would be hippicritical to call it cheating if she slept with a Bajoran man (both of the same "race" and humanoid), but he could link with as many Changelings as he wants. It is an intimate experience -- even more so, because thoughts are shared as well. Kira doesn't share herself with anybody but Odo -- she loves him and only him.

Kira's force of will and love in this episode is very moving. For one brief moment in their relationship Odo had doubted her love and where he belonged, and Kira came through, showing one of the many reasons that Odo fell for her in the first place -- her fierce loyalty. When she gives her heart, it's for keeps.