Yes, I said it would be really hard, but I think you'll be glad you did it.
Another thing I did during this time (remember, my H had already said he was moving out) was I got him to finish some projects around the house - including one major bathroom repair/remodel project. Thank goodness I pushed him on it, because he ended up asking to sell the house just a few months after he moved out, and with that project done, it was relatively easy to get the house ready for sale and we got top dollar.
I know one of you might stay in the house, but still, getting him to finish up any nagging projects before the you-know-what hits the fan might be useful to you in the future.
Also - make xerox copies of ALL financial statements, old tax returns, etc.
And, you might want to gather whatever evidence of the affair you might need. In most states, it doesn't seem to matter legally, but you might need it just to break through his denials to you or his parents.
Hope you have a nice Thanksgiving with the family, carve out plenty of time for yourself doing things YOU want to do over the holiday.