A common mistake is using „since“ with a period of time (like „two months“), which is incorrect. In English, „since“ is used for specific points in time (e.g., „since last week“, „since January“), while „for“ is used for durations (e.g., „for two months“, „for three weeks“).
The rule:
Since – used for specific points in time (e.g., since yesterday, since January).
For – used for durations or periods of time (e.g., for two months, for three weeks).
W: I’m in a situationship with him since two months.
R: I’ve been in a situationship with him for two months.
