Mapam, so much of your situation resonates with me - I sit reading your posts and nod to myself, thinking "yeah, that's what happened to us...yeah, that's how I felt too."
It's all about him, isn't it? These men are so self absorbed, it's breathtaking. He went because he didn't have enough sex. And he thinks that now he's told you this, you will have a light bulb moment, have him back, and as well as juggling work, home, and keeping all the plates spinning, you'll accommodate him more frequently in the bedroom, and all will be lovely.
Is he living in La La Land? Does he not realise that he wasn't a husband to you, he was an extra child for you to look after? Does he not see that women need a partner, a man - not an extra kid to look after. "Playing on his computer". Yes, mine spent hours on stupid games (and I later found out on porn sites), whilst I ran around like the Duracell bunny, looking after 4 kids and him. So that was 5 kids then. And then they wonder why we don't want to have sex with them after a day spent exhausting ourselves trying to get everything done. For me, sex became another chore, like the ironing, something that I felt I had to do.
You are a grown up, and he sounds like a big kid. All about him - no idea or consideration about how you feel, your needs, how he can change to make things better. It doesn't even enter their thick heads. Mine didn't talk, be affectionate - anything. I too used to look at other people, other couples and feel a pang of extreme sadness that I didn't have what they had.
I think you realise that there's no going back. You've put so much time, effort and emotional energy into trying to make this work before, the though of having to do it again, leaves you feeling exhausted. This is because he isn't taking any of the responsibility - he's blaming you for not having sex enough, which is rubbish. He needs to look at his own behaviour and then he might realise why you didn't want a lot of sex with him.
You say you're doing well on your own and you're finding your real self again - I know how that feels, and it's a real surprise. I dreaded being on my own, and amazed myself by thriving. I felt like a big oppressive cloud had been lifted.
I thought the relief and happiness would pass, and I too would come back down to earth with a bump - but I haven't. I'm calmer, content and happier now - all the resentment I had, of giving far more to a relationship than he did; of trying to justify his crap behaviour to myself and others, disappeared when he did, and I felt lighter in my heart than I had done in years.
You have a good holiday, and if you need to tell him anything, tell him that you need time and lots of it; but that as you feel now, there's no going back. He's realising that the grass isn't greener, and he's seeing you cope and cope well. Huge dent to the male ego, that is. Just because he wants to come back doesn't mean that you have to put aside your happiness any more, and compromise what you want. You're separate people - you're not responsible for his happiness any more - you never should have been in the first place. Just focus on you, what you want and the kids. Time for you to be the selfish one - your days of enabling him are over.