So about 20 years ago when I was 16/17 I had a boyfriend for about a year, went our separate ways (I ended it, he was gutted) quite soon after he then met someone else got married and had kids.
Over the years seen him & wife around handful of times, and we are polite etc.
On Saturday I got a Facebook message from him, saying "hi how's you" was busy didn't respond and didn't think much of it, the next day my sister (who works with his dad) told me that they had recently split up (like very recent 2 weeks max) his wife choice she just said she didn't want to be with him etc.
So i thought ok that explains the message considering we are not Facebook friends etc and was a little like for god sake what is it with men, suddenly he wants contact!
So I still didn't answer then today I get this message from him " prob should of mentioned in my message him single now" 
No I have no Intrest in him, don't want to meet him etc but also don't want to be rude, what can I reply kind of ending the convo?
I was thinking something along the lines of "sorry to hear that, take care of yourself"
Oh and he will 100% know I'm also single