Is it manipulative to make a proposal deadline?

I've been with my boyfriend (25M) for 5 years. I've told him I want marriage and he asked for more time (conversation from a few months ago) I don't want to force him into it but also don't want to wait longer than I already have. I told him last convo that I'm not going to wait around much longer. Is it better to keep the deadline to myself or should I share it with him?
Is it manipulative to make a proposal deadline?
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