I can't seem to find where you talked about his schedule, so please correct me if I'm remembering wrong: P stays 2 days/week with you, and then 2 days/week with another gf. So, where is he the other 3 days a week?
I am just wondering, can't you ask him to expand his time with you in some way? Like to 3 days/week. Or to have a thing like he spends a full week with you every 1 or 2 months or something like that, and still keep the rest of the month 2 days/week. Do you think that would work?