Is this guy just bullshiting because I already rejected his sex after talking about having sex a lot and sexting a lot and getting close ?
From what I see here, he's looking to hook up still. The feigned disinterest is an attempt to get you to admit you want him too and when he brings up his other mistress its clearly to make you jealous.
He's telegraphing his desires as well. They double as hoops you need to jump through (a great move on his part). He's telling you about immature, crazy women hoping you see that you'll have to be the opposite to be with him. And for good reason, as extra- marital affairs require two even-keeled people- otherwise they get messy quickly.
You get a C- for being a bit over-excited on the messages and not responding to the cues he's giving you. You two will likely never be "just friends", but if you're looking for only sex, he's putty in your hands if you can work on showing him you're mature, and emotionally stable.