Welcome porcha. I have done similar things. I tried to kiss my girlfriend's best friend at a party once and habitually would flirt with my friends' wives/gf while drunk.
I now know that I had social anxiety as a child/teen and alcohol allowed me to come out of my shell. For a long time, it worked, but as I built up a tolerance I needed more and more to get myself to be sociable to the point I was drinking myself into stupors where I couldn't really control my actions or words. That's when I would make a complete a** of myself.
You're not alone in your shame. Best we can do is stay sober and let our true good selves shine through.