Low Lying Placenta

At 14 weeks I had an ultrasound done to measure the cervix. In the ultrasound they found the placenta was sitting too low (over the cervix) They told me not to put anything up inside my lady part...which means no sex!!! Not having sex with my husband is so hard. So they said in 4 weeks we’ll check it again. This week at 18 weeks I had another ultrasound and it’s still low. Again, no sex and another ultrasound in 4 weeks. It’s so hard not being intimate with my husband like I’m used to. We’ve been improvising as much as we can but I’ll also do anything to keep my baby and myself safe. Has anyone else gone through low lying placenta this early in the pregnancy. (I know it can happen during the 3rd trimester as a placenta previa) Just wondering if during early pregnancy how long it took for placenta to move upwards?