I am just starting out in my path also. Puppy is great with the advice as are many other people around here.
I am re-reading DR because it just hasn't sunk in yet. I got the same speech you did...not in love, haven't felt it for a while, maybe I never was. I found out he does have feelings for someone else and I truly believe if she were gone he would try to turn his attention back to our marriage.
I agree with the others. Decide what you want to do first. If you want to fight for it, read read read read.
Off to follow my own advice.
Me: 33 / H: 36 M: 10y / T: 14y 3 kids BD: 2/22/14 Live in separation 3/8/14 H consult lawyer, says filing asap 4/24/14 H moved out 4/25/14 2nd time around. 1st separation 4y ago lasted a month