I have a DS who is 6 and his relationship with his father (my ex) wasn't the best for a long time. DS has always went EOW (ex stays with his mother) and some other dates for family events/longer during holidays.
Ex has a very 'the world owes me' attitude and blames his lack of an early relationship on me as I didn't 'facilitate' this, despite the EOW agreement. Obviously it had nothing to do with his drug problem and complete lack of interest.
Ex got clean and still lives with his mother. DS still attends EOW. Ex has little to no contact with DS outside this time and still relies heavily on his mother for childcare. DS doesn't even like talking on the phone to ex anymore as it's always about ex. DS has a great relationship with his paternal grandmother and enjoys her company.
Ex and I do not see eye to eye, partly due to his behaviour early on in DS' life and partly due to him being emotionally abusive, csa issues, theft etc.
I am now expecting a LO with my new partner, due date approaching quickly. DS has alwas referred to my boyfriend by his first name. However, last night DS asked my partner what the baby would call him (partner) and partner replied "dad". DS then asked if he could call my partner "dad" as it would make him feel more like a brother to LO and admitted to calling partner dad when talking to school friends as, in DS' words, "you aren't my dad but you do dad things with me so it's like being a dad". This was completely DS' idea and it has never, and will never, be forced on him. I can see his reasoning and understand that at 6 it must be confusing to know his brother will call partner dad but DS calls him his first name.
He has spent the past day and night calling partner dad and his own name. I still refer to partner as his own name, until DS either stops or assures us he wants to stick with dad.
I personally don't see anything wrong with this as it has came from DS completely. I'd never tell him he was wrong for this. However I know ex will be up in arms about it and would like to know, before the abusive texts come through, aibu in not stopping DS/not thinking DS should be forced to call partner by his first name given his reasoning?
For the record partner and I jointly own a house, aren't engaged, but have never forced DS to call anyone anything. He still refers to partners parents and siblings by their first name, not gran/aunt etc, by his own choice.