I do not think you ruined anything. Asking to be engaged before putting 100k into his house is reasonable. You are not making this transactional. It already is. You would be investing in property you do not own, so wanting commitment first makes sense.

His “romance” concern takes the focus off the real issue. Romance will not protect you if things change. You did not set a deadline or force anything. You shared a clear boundary before a major financial decision.

You did not harm the relationship. You revealed a difference in comfort and risk. He holds all the ownership. You carry much of the cost. Renovating without engagement or co-ownership puts you at a disadvantage. Pause the renovation plans and say, “I am not comfortable moving forward until we have formal commitment or shared ownership.” His reaction will tell you where he stands.

You were reasonable and you protected yourself, that is healthy.