OP i never been shocked and speechless before over posts on mumsnet but your post stands out. For all the wrong reasons.
Afew stand out for me that a red flags here ;
You fell out with your family and your partner helped you through that -( this is a classic mo of an emotional abuser who dettaches their partner from their friends and family)
Your ex's emotional blackmail of past relationships- they have no relevance to your relationship. Yet your DP is wanting a DNA with no evidvence. This is not a normal request,you can argue you which way but its not normal in a loving caring relationship.
You ask advice on a forum which you never used before and do not meantion friends has you DP alienated them?
You had previous miscarriages so you could of got pregnant. Did you do this on purpose to mend the relationship?
You sound so naive and incredibily immature to think even think if you have this test that you will sail off into the sunset and be happy. HE WILL NEVER BE HAPPY. Adding the stresses of a newborn will only make it worse not better. It doesn't have to be physical to be an abused Emotional and physological abuse can be just as damaging if not more.
Many ladys talk about their experiences and at the time don't realise they are victims of emotional and physical abuse until they leave. You defend his actions and take offense when people are trying to help you.
You don't want a prem baby or risk a still birth. My mam suffered a still birth 40years ago. That stays with you for life.
I prevously worked as a healthcare professional, i assisted with the health vistor on my placement to moderate and high risk couples.I hope both your midwife ( and when you H/V does her home visit) flagged this up so they can keep an extra eye on you and the baby. Your emotional well being effects your baby to if your not happy neither is your baby.
Sometimes you need someone to give you the hard truth and even with the little brief in your OP is enough for posters to tell you not right and somethings a miss. It would be different if you had your own doubts.