Need some advice

Danielle
Ok so I'm a member of the Mormon church. With that being said. I'm not a virgin I was inactive for several years I was even engaged and lived with my fiance. Well that relationship has been over for some time now. I started dating again and became active in my church again. Well I am nearly 37 next week in fact and I have been dating a young man who is 35 since August. We have never said we are magnagomose but I haven't been dating anyone else. He is I mean was a virgin even at 35. He has excepted me and my past which has been really great. With that being said, he came over other night to tell me he had sex with a women a couple of weeks ago and she already has three children and here's the thing she is saying five days later that she is pregnant. Well he was expecting Me to yell and scream but like I said we never said we were managomose we had a very long descussion where I told him my feelings for him and the situation but said you have to figure it out with her. But here's my thing as a women and my question since I didn't have a cycle for nearly 19 years with endometriosis and birth control and I have no kids and I have only had a tubal pregnancy. she is saying five days after sex she is pregnant and is giving him a date of Nov2015 of when she's due. Now I'm probably cutting him loose after all of this because I'm nearly 40 and this is a lot of Drama but is that even possible five days after sex that lasted as long as a forest Gump min to be pregnant five days later. I'm just simply confused.