Vick Chamberlain, a terminator from the Terminator: The Sarah Connor Chronicles TV series, poses as a husband of city manager Barbara Chamberlain. He/it was sent back in time to help create a traffic surveillance network that Skynet hopes to use in the future.
(John and Cameron are watching a playback of Vick's memory)
Barbara: Vick, god, you poor thing. You're up again? I told you, just take one of my pills. Fine, babe, come back to bed. I can't sleep with you standing there like a statue.
John Connor: Was that thing... Married?
Cameron: The T-triple 8 is an advanced model infiltrator.
John Connor: Yeah, but I don't think she knows. I mean, is that possible?
Cameron: She would not be the first human fooled by a machine.
The above transcript, form the 1x08 Vick's Chip episode, states that the infiltrator models were exceptional at deceiving humans.
is it mentioned in any Terminator movies that terminator robots had sex with humans because of their missions?
I would say it's implied.