I've never been married, but all my friends and family are...

From what I've witnessed and been told, whatever issues are present before marriage, is only exacerbated after marriage.

Not because marriage is shyt or makes things worse, but because you'res stuck with facing them 24/7... So in my humble opinion, his insecurity will not get better with marriage, but marriage will definitly provide him with a nice platform to push your buttons and control you up close and personal.

For whatever reason you're actually considering staying with this man (I admit I don't see the appeal at all) please realise that issues need to be worked on prior to tying the knot, knots don't make them magically disappear.

Goodluck with everything, I will be bowing out of this thread now for personal reasons.