Spies actually do have issues with that where they lie, form marriages, and even have kids under false identities. It actually is a real problem since the spy tends to piss off after the job is done leaving questions about rape by deception, what to do with kids, legal stuff etc. Sure it gets the job done but as a result you end up with all sorts of legal issues nobody has a universal answer for other than don't do it so we don't have to go down the rabbit hole.