Should I put my name on the deeds or is a will better?

I've been with my partner for 10 years now and we are about to buy our first home together. He already had a house of his own which he had rented out to tenants while he lived in my rental house as I didn't like the area of where his house was. He has recently sold his house so we can buy one for us. I have two kids from a previous partner who live with us and he also has two kids from a previous partner but they don't live with us. He is putting about $90,000 deposit down on this new house of ours and the loan is in his name alone. I've told him that in the will I'm happy to get less $90,000 seeming I never had anything to do with that other house and he had it before he met me. I felt I should be on the deeds or is a will enough if we make one together that can't be changed. I'm afraid in the event of me dying or him dying my children will get nothing and his kids will get it all which isn't fair considering I work and although I'm not directly paying the mortgage I will be paying all bills food etc. I'm also concerned that if he has his own private will it can be changed is it better to just go on the deeds rather than rely solely on a will.

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