How Do I Know When It's Over

We both do the same job and often work together and it causes conflicts. He says I deal with my issues with working with him sarcastically and in a "nasty tone," which has happened. I feel even when when I try to be calm and problem-solving, he doesn't like constructive criticism and I'm still the bad guy. I think we should separate our professional life from our personal more but he has noted that disappoints him but could work but it may have already ruined the relationship. He has stated that he is drawing this line about what he will put up with with my behavior and I just don't think it's accurate or fair but if it's the way he feels, I will respect it.

We both feel mistreated, alienated, and not heard. If he is attacking when speaking to me, it's because he says he has felt attacked by me. I think we are both responsible for our own actions but he often uses the fact I have started a conversation off the way he doesn't like, I "start it."I admit I don't always handle things calmly and collectively because I am an emotional person. There is no cursing or name-calling, just passive aggressive horseshit when I feel like I'm being burned in a business sense, specifically by him. I feel like we do favors for each other in business but I what we have to offer each other is very different. We don't see eye to eye when it comes to handling these issues about work but we only have disputes about work.

'When we are together and things are nice, it feels very fun and nuturing and we enjoy talking about the craft of the work we do and going on walks and just talking for hours. In spite of our differences, I felt like we could work through them and learn to communicate better. He has stated this ultimatium about my behavior and it feels like he isn't taking accountability for his role in it and I just don't know. It feels so sad. I am a person who keeps trying to make things work even once they are over. It seemed like we were building a future together but now it just seems like I make him unhappy because of these work disputes. Due to our schedules, we don't see each other leisurely often - mostly just on Fridays and Saturdays, but he is not here tonght because of our most recent argument. I wish I could just accept that things end - I have had break ups before and it seems like this is going there and it's sad because he is a very wonderful and thoughtful person who I believe cares for me deeply but who can also become cold and callous and nasty when he is mad as much as I become passive aggressive and rude and nasty myself.