I've been in a polygamous relationship with 2 girlfriends no problem. My last ex only had 2 month long relationships and I lasted a year with her. The issue is how sensitive women are, I think they overestimate how well they are going to react to any kind of behaviour, and when it actually happens they start brewing and then jump ship.

If its something important, I'm going to be honest, but its always going to be unpleasant, and most women just wanna have fun all the time and hate negativity. Those times I spend hours going over what I'm going to say, and usually it goes down well when I do.

I know this sounds sexist, but in general it seems women are far more naturally gifted at saying the right things in the heat of the moment. So they expect the same from men, my gf has never been out of line ever, even in the most heated times. I am in always in awe at how well my gf handles herself. Myself, its basically a gift, my gf is constantly shocked at how bad I can phrase things that she ends up bursting out laughing while confirming no sex for the next week.

As someone with autism, I cannot just open my mouth during emotional periods without carefully planning out what I'm going to say, every single time I've done that I've completely destroyed the relationship in the space of 5 minutes, and I've gone through a ton of relationships.