Concerned about retained ovarian tissue

I feel a bit dumb asking this but... I have 1 female, 1.5 years and spayed. 1 male, 10 months intact. In the last week he has suddenly started sniffing her vaginal area constantly and in the last day started humping her non-stop, clearly not out of excitement. And she seems to be accepting of him, where usually she is annoyed and gets him off. And the area around her lowest nipples seem a little fatty? Maybe I'm wrong? I'm just worried about retained ovaries. Does anyone think this sounds like it or is this normal for males and she isn't having symptoms herself?

Hello - this does indeed sound like a season.  How long have you had your dog for and is she definitely speyed?  I don't know her background - you may have taken her for the spey yourself in which case you'll be pretty sure, but if not have you vets' notes clarifying this with the correct chip number on?  If she has been speyed, retained ovarian tissue sounds to be worth investigating - if not, you might want her to have a pregancy scan.  There have, at various times, been effective 'misalliance' injections available to promote early abortion - this depends on your vet, your personal ethics, the supply of the drug which has been a 'thing,' the appropriateness given the situation (future breeding intentions etc) and on catching a pregnancy early enough.  We definitely reccommend speaking to your vet.