I would get your MW to have a sit down with him, one on one if needs be.
DH was totally against it for all the same reasons and once the MW had explained what happens and we put in place a plan if anything should go wrong he came round ( he had no choice really

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I had a home waterbirth and it was the best experience. You just feel so empowered. Theres nothing like being in your own home it just feels ''right'' I was the first person to touch and hold my baby . And showering in your own shower is amazing.
As for mess, DH used a pump to drain the pool and there was a load or two of towels and such. The MW takes it all away anyways.
We have a 'spot' too. Right by the couch from when I stood up after the first BF . I won't have it cleaned either