Husbands weight gain

I need some advice. So my husband has been gaining weight during my pregnancy which wasn’t a big deal. I know it is common for men to also gain some weight while their wives are pregnant. Now our daughter is 2 months old and my husband has gained quite a bit of weight. I’m really noticing it in the bedroom. His belly presses on my body more than it used to and puts more pressure on my hips and back (which already feel weaker due to first pregnancy/birth)... I didn’t notice while I was pregnant because he would keep his weight off of me because of my pregnant belly and what not. But now I notice when we have sex especially when he goes hard like he used to. Over the past year or two he’s told me to tell him to exercise (in order to remind him and motivate him to do so). I do, but he has recently said that I am not stern enough and almost blames me for not making him exercise. I told him that he has to want to do it and that I don’t want to have to get mad at him to get him to exercise. Anyway. Any tips to motivate him? I would like to go exercise with him but I’m breastfeeding our daughter on demand and she eats like ever 1.5 hours and isn’t good at napping.