NC because this could be outing.
I used to work at the place where DH works now. My colleague (Jack - fake name) when I worked there is now DH's boss. Jack and I were VERY close friends. We hung out a lot, messaged a lot, got on really well. There was never any attraction there from either side - not my type at all. Some of our interactions were somewhat flirty but the same way you'd flirt with girlfriends on a night out - not actually sexual at all.
I no longer work there but DH now works there (DH and I never worked there at the same time). I was under the impression that Jack was now a closer friend of DH's than of mine. Jack has recently broken up with his partner and we've been talking a fair amount. He comes over to the house a lot (usually DH is here too, has dinner with us, plays with the kids etc). Over the last week or so, Jack's started to message me a bit differently and, when he's drunk, the messages have become a bit sexual (as well as a few comments made in person). He's said comments about my body, about having been with married women before, about what I'd be like in bed etc. A couple of messages have been exceptionally explicit, saying things that he's fantasised about doing to me. I've mentioned bits and pieces to DH but not been completely open with how brazen a lot of the messages are - DH was there when Jack said about how being married wouldn't put him off sleeping with a woman. I've mostly tried to laugh it off and shrug it off because I'm aware he's in a really bad headspace and he's a really important friend to me - he's definitely just projecting his loneliness/depression and trying to be someone he isn't (the typical "I can't get my heart broken again if I act like a player" act).
I'm concerned that if I tell DH everything, I'd make his working environment difficult. DH can be a little bit hot-headed and possessive of me. I'm also aware that Jack is going through a really tough time and needs some support. What do I do here?