AITA for not wanting to go to my dads wedding after my mom passed away?

So im (20M) and my mother recently passed away a couple of months ago in February, and her and my dad were married for 38 years together. Me and my siblings had a really close relationship with her, she was our best friend, the glue that kept the family together. But maybe only a month after her funeral, my father was already starting to go on dates again. Me and my siblings thought it was weird at first but we didn’t think anything of it.

Continue on down the line, he reconnected with a woman that he knew years ago, from when he was in his teenage years, and seemingly she saw the video of my moms funeral online and texted my dad on facebook, wanting to check in with him, and see if he’s alright.

After that point, a couple weeks later he then sat down and told me, my brother, and my sister in law that he’s talking to someone new, but they were just friends talking. Well, a couple months later after that point, I started seeing my dad less and less each weekend, until he just has the routine of always leaving Friday and not coming back until Monday because she lives in Ohio. And the more he went, the more they got closer until they started dating for a bit, and then got engaged. They’ve even started building a house together down where me and my dad live, which im moving into because im still a college student.

At this point, neither me or my siblings agreed with the fact that he was doing this as we felt it was weird. My brother even cutting off contact with him for a bit because of it. We’ve explicitly told him we don’t want to see her, or have anything to do with this new woman in his life. But as stubborn as he is, he keeps bringing her around after we tell him no.

Now they’re planning on having their wedding in December in Ohio, and they invited me to come.

AITA for not wanting to go to this wedding?