Relationship problems please help!

So, I’d just like to say first. I really want to see how we can make this work. What improvements we both need to make and any advice from people with experience or knowledge is greatly appreciated.
So 25(W) and 32(M) have entered a relationship 2/3 months ago now after having dated since January.
This is genuinely the best man I’ve met and we’re basically completely compatible other than our egos both being huge.
Also, he has a child, I never thought I’d wanna be involved in that kind of dynamic or situation but the child is amazing and honestly I’ve been falling in love with them and the whole dynamic.
This however means that the ex is still obviously very present which is mostly fine because they seem very nice and respectful to me as I am to them however I’m unfortunately a very jealous person so I’m trying to get over that. I suffer a lot from retrospective jealousy and seeing the ex kind of makes me think of everything they might have had and what if I don’t give that. Idek. I am a confident person but I doubt and analyse things until I bring myself down.
We’ve had some very big rows the past few days and we’ve both said some very hurtful things because of our egos, and I’m having trouble letting them go and not almost proving him right and being the worst version of my self to push him away. Also he’s now called me his exes name twice and when I mentioned that he said he’s actually called me their name many times but catches it and doesn’t say. And it’s just from habit because they were together for a very very very long time. I do believe him however it still makes me super super uncomfortable. I’m not a trusting person by nature and I doubt and analyse things a lot to try and stop myself from getting hurt.

We both reallly want this to work but I just don’t know how to deal with the name thing, my ego and retrospective jealousy, his ego and the hurtful words while arguing. Happy to receive advice, reading material or anything.