I need advice! (Long btw)

So my fiancé is army and based in germany. I'm pregnant and we decided to get married cheaply and quickly so we can get a married quarter in germany so we have somewhere to take our baby home. We have had a planned for months to get married in secret in a registry office without a reception etc. We wanted this as I'm disabled, pregnant, (i would struggle with a big party and entertaining guests) it will be cheaper and we don't have to be guilted by our families into "what they want". We had this plan. We told my soon to be in laws about the baby and that we're getting married. However they kept pressuring my partner into making plans and telling him to invite family. So he told them about our plan...no family, no parents!!! Now they have said they won't help with the baby (they wanted to buy a cot and a pram) unless they come to the wedding! We tried to explain that there will be no point in travelling miles for a 10 minute ceremony and no party or no meal afterwards. But they won't have it. They are very manipulating and controlling!

I want a big wedding but we can't afford it especially as I can't work now as the pregnancy is really effecting my disability, we're young and have a baby, furniture etc to pay for. So I decided I want to have a small wedding with just us. But now either way I can't have what I want. It's my wedding day!

I dont want to invite my parents as my father is abusive, my stepmum is horrible and if I invite my mum it will cause arguments with my dad and his side of the family. But my partner has now said he wants his parents there but needs me to say yes....I feel like an arsehole

I don't know what to do! I just wanted one day where it wasn't about anybody else but it was all about us.

I need advice...I'm not sure whether I'm being selfish and stubborn or I actually have reason to want what I want!