Hi. I'm new here too. I think we probably all have regrets about how we have behaved in our relationships. I know I do. But, you are ahead of so many people because you have admitted your wrong doings.
In most cases, I don't think one person alone can be held responsible for the breakdown of a relationship (unless there was abuse involved).
I am in the beginning stages of trying to change my behavior. I haven't been at it very long, but what I have noticed is that our behavior and actions really do affect those that we love.
For so many years, we held things in in our marriage. Now, I've turned into a screamer. It's all about self control though. I have to use a lot of self-talk to get me through those times where I feel like I'm going to lose it. But, I have faith that I can make changes. I think anyone can if they try hard enough.
I'm sure others will be along to give you more suggestions. Good luck with everything.