Is she pregnant with his child?

Okay, I and my other half absolutely adore each other. He’s an amazing guy, everyone loves him and he is 100% honest (sometimes too much so!) I completely trust him. We became exclusive to each other in March after realising we like each other, but due to complications in my life, we waited until May to become an actual item, ie, investing proper time with each other. I know he’s been 100% faithful and we are both very happy. I know before we got together he’d been single for a year and during that time he openly admitted he’d had a ‘friend with benefits’ type situation, but it was incredibly casual and they only met every 2 or 3 months. He last saw her in February, which I have always been aware of. He told her not long after that he’d met someone special and it wasn’t right to carry on with what they were doing because he thought I could be ‘the one’. We’ve since established an amazing relationship and life has been great. Then she contacts him out of the blue and tells him she’s pregnant, that it’s his and she’s keeping it. Thing is, I spoke to him about it and he told me everything, including that he’d not ejaculated inside her and I know as I have a close friend in family planning that the withdrawal method is 96% effective against pregnancy. sexpromo.ch I also know him and that he is very conscious about taking risks and wouldn’t have just ‘forgotten’. His first reaction was to offer her support because he thought it was someone else’s. He’s a family guy who had a child in a previous long term relationship and wants to settle down with one person. I am aware it could be his, but it just seems nuts!