I'm feeling a lot of feelings today and just need to put it somewhere and maybe get some feedback. Long story short, my partner (29mtf) and I (30cisF) have been together since 2014 and she came out as trans femme about year and a half ago. When I found out I was 4 months pregnant last year, she told me she would wait until after the baby was born so we wouldn't both be in hormonal unpredictability/rollercoaster at the same time but wasn't able to and started HRT when I was a little over 5 months pregnant.
We now have a nearly 4mo and today is father's day and for some reason, it makes me so so sad that my partner doesn't seem to feel proud at all to be our sons biological father. Doesn't even want it to be acknowledged and feels upset when people say it. I know that part of it is that being acknowledged as the dad too often or at all can cause dysphoria so I'm trying to understand that more but I've seen some trans woman who are proud to be the dad/father but just prefer to be called mom and referred to as mom and I sort of anticipated that to be the case in our family but that's not the case and I guess I just didn't expect to have so many feelings about it. Sorry for the run on sentence.
I am working with a therapist to sort out all of my issues with things but this particular one has really been bothering me and I don't know if I'm just being a total asshole or if other people would/do feel similar things in this type of situation too.
I wasn't prepared to share the mom title (I know that perspective is seen as possessive and I've been working on addressing those parts of my brain) and that has been really hard on me but I've been trying to adjust and accept it so my partner feels celebrated and equal as our son's mother. But it has been more difficult for me than I anticipated and I'm struggling to navigate that.
So if any of you have any thoughts or experience to share, I'd really appreciate it. Please be kind if possible, my hormones are all over the place rn and I'm extra sensitive atm 
EDIT:Thank you for the feedback everyone, and an extra thank you to those who tried to speak kindly in their responses and recognized that I wasn't coming from a place of malice. I also really appreciate everyone that shared their personal experience

After rereading my post, I realize I didn't articulate my feelings properly because I agree with and already felt a lot of the things that were mentioned in the responses I've gotten.
She goes by mum and we chose to celebrate her on star wars day since it's one of her favorite days, and I think the plan was to just not celebrate father's day at all, but what was throwing me of was the unexpected feelings I was having about it. My post was mostly just me feeling a lot of things I wasn't anticipating feeling and I decided reaching out to gain more perspective from people who had experienced something similar was a way to maybe help me navigate that.
To clarify, I did not and do not expect my partner to want to be called dad or father, and I didn't mention father's day at all to her because of that. I only made the post cause a family member messaged me to tell her happy father's day and the emotions that came with that were complicated and I needed to vent them to somewhere that they wouldn't hurt my partner.
Please remember this sub has the potential to really help well-meaning people to understand or seek support to navigate tough situations with their trans partners, and being judgemental or condescending doesn't help teach people, it just hurts them and adds another obstacle in the way of them truly understanding to the best of their ability.
Thanks again everyone. I'm going to try to reply to some of the individual comments when I can but our little one is beginning teething so my spare time is slim atm.