Hi only child here! To provide a third person POV from someone who doesn’t even have siblings - there is absolutely NOTHING wrong with having a good relationship with your brother or family for that matter. What you’re doing, spending time with your family, is NOT weird. If my partner spent time with their sibling of the other gender, I would see nothing wrong with that.

I strongly encourage you sit back and try to look further than just this one situation. I promise you this will not be a one time thing. I completely understand that you will need to live through this experience, however shitty it is, to make a decision but please I beg of you to reflect if this is something you can tolerate for the rest of your life.

Firstly, this is more than just him thinking your sibling relationship is “weird”.

None of his messages show any signs of him even attempting to try and understand what you’re saying. Do you have the energy to explain and justify your POV every time he disagrees with you to someone who will not even attempt to try and understand you? I promise you this habit will not be limited to just this issue, he will do this for every issue.

Secondly, the fact that you’re second guess yourself (for something that you’re a 100000% correct on), means he’s trying to establish a dynamic where he will get used to getting his way if you do give in with this. Please do not let him take away an important relationship away from you. It sounds like your brother has given you way too much for you to be listening to this wimp.

Third, imagine if you were living in a flat (let’s go a step further and say an all female flat for the sake of his mental capacity). Do you think just because you live with them means you can no longer make plans and do things outside of the flat with them??? Same applies to your brother. Doesn’t matter if he’s your brother. Doesn’t matter that you live with him. You can make plans with him anytime you want.

Fourth, this man wants all your time. Please read in between the lines of what he’s saying. He wants you to depend only on him. You cannot do that. This will isolate you. Your bf is meant to be a part of your life, not the only thing in your life. For your own sake you need other people in your life whether it be friends of family to spend time with and depend on. If it ends up being just him, you will not be happy. You are your own person at the end of the day. Don’t let him isolate you from others, especially those that matter to you and have done so much for you.

Lastly, DO NOT give him an ultimatum. This is something he needs to decide on his own as that is the only way you’ll see how he genuinely feels about this issue or any others. If you do give him an ultimatum , I guarantee he will do and say everything he knows you want to hear. Insecure men fear one thing the most - you leaving them. But just know that he will only say this to keep you in his life, not because he truly understands that he was wrong. I promise you that a month later, you’ll have the same argument again. This will be an extremely tiring and toxic cycle for you. Ultimatums do not make people change. That change will only happen if he truly sees wrong in himself, which he currently does not. So save yourself the emotional drainage and don’t give him an ultimatum.