Before I start this is kinda gross so sorry in advance:
I really hate pooping, like sometimes ill try to hold it till its impossible to not go. It started almost 2 years ago because my parents traveled for a year and my little brother came to stay with me. (i was 18 at the time and he was 16) He shared my bathroom and peed allover (like seriously allover it looked like he tried to cover the seat the floor and sometimes the wall) it was so disgusting and whenever I asked him to clean it up he refused. (i talked to my parents and told me they would try to take care of it but obviously they can make my little brother aim is penis to the toilet from asia) I was going to college with a full load of classes and had an exhausting part time job the last thing I wanted to do when I got home was scrub up some1 elses pee. So whenever I had to poo I had 2 stand up with my feet far out to the side of the toilet (not an easy thing to do) and over time my head just started telling me I didn’t want to poop. Now he is back(my parents are writers and my mom is on a book tour this time) I still havent been able to get over the not wanting to poop till I have to thing, now I have 2 bathrooms so it will be better though. How can I learn to hate poos less (i know weird question) and could i have gotten anything wrong with my insides from holding it so much? Would it be a good idea to take something such as exlax once a week to try to clean out because I don’t think ill get over the pooping thing right away?

(btw I have no other problems with my brother except for this so dont make mean comments like kick is ass out or anything)
main facts: bad situations made me really dislike pooping hold it to much now, how could that effect me? any good ways 2 make pooping less of a dislike? should i take ex-lax or something regularly to try to flush whatever might be left?