Mr. Me, it is a difficult spot you are in right now. You have read all of the homework cadet has postd for you? I hope you have.
The mist important thing to start with here are the 37 rules. I want you to read then and reread them. Many folks print them out and write notes as reminders and the like. Make sure though that this is put somewhere she will never access like a drawer at work...often the was will snoop on us so it is important to keep this stuff away from them, they will only see your efforts as manipulation and ignore your good intentions.
If she has stopped saying ILY, I would definitely not try at this time. It is pressure to her...you are looking for reassurance from her and she does not want to give it you for whatever reason.
Pressure on the spouse who wants out is like a noose for your marriage relationship. the more pressure you place on this right now the tighter it will get and the harder it makes to breathe.
She already knows you love her. You do not need to say it and she definitely does not want to be reminded of that every time she sees you.
Please read and reread those rules...the biggest impact you can have on your marriage right now is giving space and taking pressure off of her. It is scary but I promise you, you will survive.