In my opinion, its no,

No one can marry with married woman,

It is safe in regards of pregnancy but not good for the health of women. So I advise to women not to have sex during menstruation period.

No, there are very rare chances during the period of one week after start of periods and the period after 3 weeks of the start of periods. Only two weeks are crucial for pregnancy, period of two weeks after first week of periods.

Majority of people like it, it is sign of life.

You are more special to him because he is doing all in internet and he is not getting all from you in real. And he is waking for you, in my opinion he deserves too much returns from your side.