Ex saying baby is his ughh

So I split with my partner and stared seeing a guy in between. When him a i split up it was 10/26. I had been on a regular period from .  10/24 my partner and I got back togeher and wanted to try for a baby ( we had a 3 year past) so we checked the ovulation calendar that said I would ovulate On 11/6 or 7 and make sure to have sex on those days. We did day and night. I got a faint pregnancy positive on 10 DPO and a good one 11dpo. I took a clear blue digital that sas I ovulated 1-2 weeks which would make te 6/7 ovulation date correct. I also remember cramping a bit on the 6th which is a sign of ovulation. If I slept with my x the 26th and didn't ovulate until the 6/7 there is no way sperm could live 11-12 days. I no it's close but I feel 120% he is just being crazy and trying to cause more issues. I just finally got a postive test yesterday 11dpo and also 1-2 weeks since ovulation. That doesn't put me anywhere close to the 26th. Thoughts? I just wanna no I'm thinking correct and the timing is right with what I'm saying.