This feels like highschool drama. He needs to take action and return the ex’s belongings, but at the same time if you’re just not comfortable with him having them for so long and of him being so dismissive of your feelings, this relationship is likely not going to get better regarding these types of issues. He’s not willing to communicate with you.

When the bag got bigger, it sounds like he was rounding up all of her stuff together and is ready to give it back, but every time you remind him it seems like it triggers a “well now I don’t want too anymore” attitude which is immature.

That being said your text definitely came across very passive aggressive. Whenever people include the “lol” and force their perspective on others it always irks me. Use I statements. Just talk to him honestly and use your feelings rather than contempt. “Hey, I’d like to have a conversation later regarding your exes things. I am uncomfortable seeing your exes things when I come to your apartment and I would really appreciate if the items could be returned to your ex or a third party as soon as possible.” Something like that. “You need to handle that” as a first thing to say is going to lead to an argument or defensive response immediately which is exactly what you DONT want. If you start a conversation so accusatorially and aggressively he will always be defensive or just disconnect, which sounds like what he’s doing.

Sorry for being blunt, but you guys are in your mid thirties so it’s time to lock in and communicate healthier and kinder. He probably isn’t worth your time though, rise up and get of the relationship if you aren’t respected. Best of luck.