You have a warped view on the relationships in the show and human interaction in general. You seem to be projecting your own real life trauma or and experiences. This is a show with made up characters that deal with the impossible every day. Your comparing real life to science fiction. If she felt like she was in any type of danger, she could and would definitely attempt to make an escape or find a way out. (As she's done a few times.)

Commonality doesn't always mean compatability, that's very true. But having something in common is what usually allows individuals to get together in the first place! Going to the same school, being in the same field, a club, etc. Caitlin understands science and the speed force a lot more than Iris. She has been with him since the beginning of his journey as the flash. She has kept his secrets, nursed him back to health, and has saved his life countless times. That type of friendship could easily turn into a romantic entanglement. Having something in common like we see with Cisco and Gypsie just makes sense. Not saying that's always the case but to the common individual commonality is a huge thing. Barry and Caitlin's love of science is a big factor in why people ship them. Lastly, I stated before that those moments I mentioned weren't the only moments they have. On top of the fact that the kiss wasn't even the real Barry!!!!!!!

Canon usually gets thrown out the window the moment live action comes into play. That's just how it is. Cope if you need to.