How does he treat you badly? What triggers his negative reaction towards you. Does it increase when he's around his friends or if alcohol is involved.
If so, I'd give him a compliance test. If you're serious about us and me, no alcohol for 3 months, because we want to look hot for the wedding (and honeymoon).
If he can't adhere to something like that, then you're not a top priority. And you definitely wont be when money gets tight, someone loses a job, the sex gets less intense, etc...
I'm married for nearly 20 years now. Build it on a foundation of trust, love and respect (and great sex). When the kids come, you will be way better off than the what if in your mind.
Also, don't let the external pressure of the biological clock nudge you towards a bad decision. Think of yourself as the old L'Oreal commercial -- you may cost a bit more, but you're worth it.