Bit of a long, complicated one and I'm just trying to get some advice or understand why I feel this way.
When my partner and I first started seeing each other almost 4 years ago, we already knew each other. I knew he'd been in a previous relationship and bought a house with his ex as she got pregnant. Although I then found out they'd never lived together as she broke up with him before they moved in to the house. He lived in the house for a short while alone, then she moved in there and lived there for around 5 years I think.
Anyway, he told ALOT of lies at the beginning of our relationship, mainly because of what I said I wanted from a relationship, having been in a pretty bad relationship previously and not wanting to put myself in that situation again. His situation didn't match up with what I wanted.
He said he had confirmation that the baby that was born wasn't his, guess what, he didn't. He just assumed the child wasn't as the ex was with someone else before the child was born, this is someone that she had known and worked with for quite some time, as the child grew/has gotten older they look alot like this other guy. So, he'd always just thought she may have been seeing them both at the same time - no judgement here from me about that, life is complicated. He's apparently never met the child or paid any maintenance. The ex split up with the guy quite a while back now, but he's still playing the father figure - around 5 years on from the split.
In addition to the above, my partner 'forgot' to mention that he was still on the mortgage for the house they'd bought, the initial period was for 2 years and he'd even renewed the mortgage with her for another 2 years because she wouldn't have gotten a mortgage deal on her own, again, something he'd forgotten to mention. Thankfully that part is all sorted now and the house was sold a while back.
While the house was getting sorted, my partner asked the ex for a DNA test, she refused immediately and said if he persued it via a legal route she would go to CSA.
The part I can't get past is that my partner potentially has a child out there. I do not want to be in a relationship with someone that has a child, regardless of whether or not they have anything to do with them/pay to them. Had I known the truth at the start I would never have gotten into a relationship with my partner. In my own life experiences, situations like this almost always bring complications at some point. My partner just sees it as there is no issue as he doesn't have anything to do with the child.
I also don't understand why the ex won't give a DNA test, said child is approx. 7 or 8 so I doubt they would understand what was going on, especially with things like Covid swab still being a thing and my partner has reassured the ex he still wouldn't want anything to do with the child, which she has said is one of her concerns.
Any thoughts or advice on this are much appreciated.