Here is an idea... is there anybody you could borrow the retainer money from? That way your H won't have to know a thing about what you are doing legally.
I don't know how your state works but once D papers are filed/served there is a time frame for response. If your H is not expecting them then he will have to scramble for an attny and chances are he will be so out of sorts about what he knows you know already he might panic and just choose *any* attny and we all know how important choosing the right attny is.
Personally I would not tell him you are retaining legal counsel but that is just me. I would take it a step further when ya'll meet for coffee and have a settlement drawn up (that you made, not your attny) and tell him this is what you expect if he would like to keep this out of court. Give him 24 hours to accept or decline your offer. People make very bad decisions when they are backed in a corner. If he declines your settlement offer, well, you know what you need to do.
I made it very clear to my H that I would not negotiate as I was given no negotiating power when he walked out on me for an affair. Negotiations go both ways and your H set the tone for NONE to occur when he began his affair. Too bad, too sad for him.
