Well, I'm not sure I'm one to give advice given I'm swirling in my own mess...but here's my perspective.
You'll see in my sitch that I've had several of these friendly/warm conversations with my H. I get encouraged by them...but in the end, it's very hard to figure out if he remembers/means what he has said OR if he is trying to manipulate me to stay on his fence (even if he isn't consciously manipulating)
I've had very bad luck sustaining anything positive. While you'd like to believe your text is going to break through the fog or interrupt his time with OM, I predict he's deleted or ignored it and blocked it out.
I had a similar situation with my H about 3 weeks ago. We had a nice conversation and he told me he thought our marriage wasn't as intimate as it should be...he then went on to say that during his affair, nothing has changed and it had gotten worse. I said I had had to detach myself from him and the pain. However, the next day, I sent him a nice little email saying I was looking forward to the holidays and I sent him a nice memory from the past. His response? Nothing. He ended up flying out that night to go on vacation with OW.
I'm more and more convinced the A has to end (and in your case, probably the alcoholism too) before you can make an impact. That isn't to say you don't want to try to do 180's, new approaches, etc. I just wouldn't get too confident that anything is breaking through.
My "new approach" is letting H know I can't go on and we need to separate if he is going to continue the A. I'm hoping reality could settle in...but, he's with OW now and won't commit to when he's coming home...so, the fog continues.
Peace and hang in there! NB
M 44, H 46 D11, D9, D5 Married 12 years PA confirmed 9/2011 I filed 3/2012 H moved out 7/2012