Hmm this is a tricky one, and I think in speech people probably wouldn't even notice if you used "with". They would certainly know what you mean. Having said that, to me it doesn't feel quite right. I would only used "well versed in", and use it with more specific questions than "circumstances", which is quite general: She's well versed in twentieth-century Russian history. I'm well versed in the tricks pupils play to avoid doing their homework. but not *He's well versed in geography. *We're well versed in going on holiday. (Though you might say "we're well versed in going on holiday to Bhutan", for example, as it references the specific fact of Bhutan being a notoriously difficult place to holiday in.) Sorry, that was probably a longer answer than you wanted :-S

Well versed in or familiar with. I think the latter would be more appropriate.

"Well versed" is generally followed by "in". You can be well versed in something meaning have a lot of knowledge about something, acquainted with, or skilled in something. Your example sentence sounds a bit awkward, as others pointed out. I would use "familiar with", e.g. My boyfriend is familiar with my circumstances.

I believe the correct preposition is IN. That said, I agree with Lenka. 'Well versed' sounds more like you are talking about a skill or academic knowledge, not your personal situation.

I wouldn’t personally use it in this context. My personal opinion. I would not overcomplicate it and rather opted for; He is well aware of my circumstances (situation) He is not kept in the dark He is in the know He knows my situation very well He knows all the details