With Faith, she was being hateful and wanted to violate and hurt Buffy.
With Roman from Possession, he was madly in love with Jess.
With Bridget, she thought her sister was dead and wanted to make things right in her sister's life (giving Andrew a good wife & Juliet a good stepmother) while also realizing that she needed that life as much as they needed having her.
It's true that Bridget held off a long time before she had sex with him. It wasn't until she had fallen in love with him and was planning on pretending to be Siobhan forever if it meant staying with him that she decided to make love with him.
I have maybe 8 eps recorded. I should've recorded them all! I want to have a Ringer season-long marathon.