I'm a 49 yo woman so I've been through my share of breakups. Very often you are left never truly understanding the reason why they ended the relationship. Whether or not alcohol is involved! You just have to make peace with that. You will probably never know.
Secondly, another thing I can tell you from the basis of my experience is this: This is NOT the love of your life. His conduct was laughable. He sounds like an adolescent, not a grown man. "Love" is peaceful, loyal, and mature. This is a turbid, toxic romance. You're getting too old for this nonsense. Good riddance.
Don't confuse having strong feelings for someone to mean that it's "love" or that it should continue.
As for your question, "In sobriety if you are already in a relationship do they still frown upon it?" It depends on the exact group he's working with and how the individuals in it choose to interpret "recovery doctrine." Word to the wise: Remain in control of your own life and steer clear of anyone who is not in control of theirs and making their own decisions.
So, I know you're hurting but just tough it out, and push this relationship out of your mind as much as you can. If you find yourself thinking about it, get busy doing something else to occupy yourself. Maybe it will resurrect in the future, and maybe it won't. In the meantime, I suggest you make some happy plans for the weekend either with friends, or a casual, happy, stable date.
Nothing makes a man pull his head out of his a** faster than moving on. Find some better company and blow this loser off.