Is this weird? Anyone else's husband do this?

My husband and I are trying to conceive. Right now we are doing the trigger shot with timed intercourse, so my husband knows exactly which days will (hopefully) make a baby.

I've noticed for a little while now, that he is way rougher on my fertile days. We typically have rougher sex anyways, but he takes it up a couple notches on those days. For example. If my hair is in a pony tail, he would usually grab that and pull a little. During the fertile days, he grabs near the roots of my hair and pulls. On a normal day, he will suck on my nipples and maybe graze his teeth a little. On the fertile days, he will full on bite them. On the fertile days he grabs me and throws me around into different positions a little rougher than usual.

I have been noticing this for several months now. He's only THIS rough when he knows we're actually having "baby making sex". Sometimes it hurts a little and I'll let him know, but other than that, it doesn't bother me. I just find it a bit weird.

Is this weird though?