My man won't cum from sex anymore

So I've noticed the past 3 weeks or so he won't cum from sex. He only finishes if I give him head or he masturbates while tea-bagging/I suck his balls (do people still say that??) and now I'm feeling so self conscious. I know I've gained like 10lbs in the past couple months and I just feel so ugh. Any ladies experience this? Is it me, is it him?