So two issues 1. being poor company and ignoring you, 2. getting reassurance.
Perhaps if you had his full or mostly full attention when he was with you, you wouldn't need reassurance at the end of his dates. I wouldn't be troubled by a partner mentioning they had a late night with a partner, but if somebody was texting while I was with them regularly, I would leave the area..at a party I would go find somebody who wanted to talk with me. If I started a relationship with somebody who did that, it would end really quickly.
When you started seeing him was he distracted and ignoring you during dates or has it gotten worse (NRE with others or taking you for granted)? DO you have actual date nights that he is doing this during? I don't mind texting or im'ing during some times when we are doing our own thing, but if I'm face to face with a partner, and left sitting there twiddling my thumbs more than occasionally, I'd stop making plans with them.
I'd definitely bring it up ASAP, because if you can't sort this out now, that could be an explosive argument when you finally address the issue. I don't see why asking for polite behavior is considered controlling, but I do disagree with GG a bit and did feel like some of your texting could read as passive aggressive. If he is feeling you are being passive aggressive, in his head he might translate that into a feeling that you ARE trying to be controlling and then it's harder for him to hear you clearly when you do bring up your actual problem. He also probably feels like he just cant win with your responses. He did text you when he woke up, unless you want to make some agreement that will make you even more stressed (like text me the second she leaves - so you're watching the clock and feel insecure as it gets later...) it sounds like you might want to find some alternatives.
Do you think you are willing to not need reassurances? Not today, but maybe give yourself a timeline of 4-6 months after you move in together, and feel like it's a good situation for you? You could ask him to set an alarm for a certain time and call or text you at that time to give you reassurance? (and I'm thinking not a super early time so he has to call you right after the alarm clock wakes him up - looks like GG mentioned alarms, and I wholeheartedly agree that serious discussions should be done in person or via letter) Did you say a chunk of this the fact that he doesn't respond to your texts right away but he always seems to do that for others so you feel envy? I really don't get this need people have to check out of whats in front of them to text. Out of fairness I expect that his other partners might ask for the same consideration, that he pays attention to them sometimes and just isn't available to text you back quickly when he's with them...but I'd say something along the following -
"I'd like to have some times we spend together where you're present and we aren't distracted by other things, including texting other people. It feels rude sometimes, like you aren't enjoying or wanting my company. I was thinking something like this might be a good compromise -I'd like this on any specific actual dates planned for private time, T/F between 8 and bedtime after we move in together, and also when we go to an event or party together and you're my partner there. What do you think of that, and if that doesn't work, do you have any ideas that might work for you?
Happiness will never come to those who fail to appreciate what they already have.