It's good to be scared - it makes one pay attention.
Married to an NT female who has been most gracious and forgiving of what I've done that shouldn't oughtta been done.
She has some serious issues of her own, so we're both working on things.
Marriage is work and lots of conscious decisions, it won't fly on autopilot.
Infidelity and rejection are always possible, it is the nature of life. We have made the required active decisions to not have those.
Same holds true for emotional or physical abuse, everyone has the potential to do that and has to make some kind of decision not to.
As to how wrong things can go:
My wife is divorced from a man who turned out to be a child molester. My brother's first marriage was to a gal who ended up trying to kill him: his current wife is every bit as good as the first was evil, she's faithful even while my bro is out of the country for extended lengths of time.
I had not been married or in a live-in relationship before this one.
It's been shown best for the partners to not be totally alike or totally different. There needs to be enough alikeness to make a connection and yet enough difference to be individuals and to remain interesting to each other.
Whatever the belief system it is shown good for both to have similar or parallel spiritual beliefs and/or values whether there are some or none - the partners will be mentally and emotionally operating based on those values and can be at cross purposes if too different from each other.
Remember, marriage won't fly on autopilot, it is something you do every day.
And cannot possibly get perfect every hour of every day. Both partners need to accept that.
There's my input.
_________________
"Every time you don't follow your inner guidance,
you feel a loss of energy, loss of power, a sense of spiritual deadness."
- Shakti Gawain