Husband Wearing a condom for anal- weird? (READ FIRST)

My husband and I have been married for three almost 4 years. In these three years of marriage we never used condoms as we wanted babies. Well our kids are now 2 years old and 3 months old. I have an IUD so we were both on the same page that we still wouldn’t use condoms. Randomly he tells me we should be more careful and use condoms since the IUD isn’t 100%. I understood that, because even though we always talked about having 3 kids I did agree we should wait a little while longer before trying (hence the IUD). But what’s a little suspicious to me is that he also has been insisting on wearing a condom when we do anal.

We’ve had anal sex before, numerous times. And he’s never worn a condom for it. Now he is. I ask him why since I can’t get pregnant from anal, and in the very off chance something gets inside my “other hole” I have the IUD. And whenever I try to initiate oral sex on him, he changes the subject or just tells me we’ll have sex instead and he reaches for the condom. I’ve asked why and he always just says he hasn’t showered. That’s never stopped him from letting me give him a blow job before.

I don’t want to be crazy or overthink things but part of me feels like maybe he’s doing this because he’s been having an affair and doesn’t know if he’s clean. I know it may be a bit of a jump to wonder that but I can’t help but think. I had our second baby 3 months ago via c section. So I was out of it recovery wise longer than with my first. What if he just couldn’t wait and went and did it with someone else? Is it weird for him to insist on condoms now all of a sudden even when doing anal? Please no hate. I hope I’m just overthinking it