Pisces with a 50 yrs old Aqua sun Pisces venus boyfriend here. We've met on a dating site 3.5 years ago.
Your love interest is intriguing, indeed. Do you have any idea how long has he been on that (dating, I suppose) site for? If he just signed in when you met, he was probably like a boy in a sweet shop....all these interesting and attractive women to meet.... You were shortlisted and made a great impression on him, for sure.
As the time goes by, he will learn that not all that glitter is gold. He will go back to that shortlist of his and eventually become exclusive with someone. The fact that he invited you to stay with him even for a couple of months suggests that he is seriously considering becoming exclusive with you. I don't see how he would leave you alone in the evenings with the line ""Ta-da for now, I'm off on a date, see you tomorrow honey!"
You come across as a bit immature, though.....living with ahem, a roommate....? That's almost as bad as living with mum and dad during your adult years. Breaking up with him at every opportunity and without an ultimatum....? This would translate in a high risk of divorce, alimony, maintenance, etc, in a few years, assuming that you two marry and have kids! Last things a man want!