I suffered severe anxiety in my late teens, and after having therapy I managed to overcome it. It still comes and goes but it was at a ‘manageable’ level - I could still live my life.
Fast forward a few years, I’d mostly repaired the damage the anxiety had done to my life - re established friendships, put more effort into self care, and genuinely began enjoying life for the first time in years. I also started dating after a couple of years being single (due to low self esteem) and got into a relationship which is where everything went downhill badly 
At first everything seemed great, but gradually his abusive side started showing (which I tried to explain or rationalise away). It started as mostly emotional abuse. Then I found out I was pregnant - he acted happy and supportive, wanted me to keep the baby and spoke of our future together, apologised for the past. But a few months into my pregnancy the manipulation, gaslighting, general narcissistic behaviour. Towards the end of my pregnancy he also frequently forced me to have sex with him, threatened to cheat on me (he already was) and worse. Once DD was born he came and went as he pleased - found out a few months later that he has multiple children with multiple women, most which he has no contact with.
After the months of therapy and work I put into improving my life I’m now 100x worse than when I started. I love DD, we have had no problems with bonding and I feel very lucky to have her - but I can’t help but feel like my experience of motherhood has been totally overshadowed . I am off work due to anxiety and low mood/depression - and have 0 free time, no childcare and rarely have a family member free to babysit. Regained weight, generally don’t give a shit about my appearance anymore (what’s the point? I never go anywhere except library/park/supermarket etc) and despite being NC with him for a few months now, i still carry around the anxiety, resentment and sadness from when we were in contact. If anything, NC has made it worse because now I have the additional sadness of my daughter not having a father.
Sorry this is so long and thanks if you got this far 
I’ve given up trying to speak to friends and family about how I feel, because all I get back is ‘but look at beautiful DD, how can you be unhappy’ and similar. I regret giving myself a lifelong tie to such a horrible man.. and knowing he has several children (3 are similar age to DD so likely conceived while we were together ) brings me down so much. I feel like I will never have closure or move on, I feel trapped, and feel like it’s ruined my entire life.. I don’t know what to do to improve things again, and live in fear of him coming back to do more damage