What to do if he likes his housemate?

I have been seeing this guy for 6 months now. We havent been in relationships yet but i really liked him. But whenever we were together i noticed that he thinks about his housemate whose a girl. She has a bf and now she moved out of the house and live w her bf.
Whenever he found something on google or fb he would send to his housemate, whenever he saw a something his housemate like he would go in and buy.
When we were on holiday together, he would go to his housemate fav store and told me stuff about his housemate. We only talked like once in three days or even a week but whenever we talked and asked about his day he would tell me about his housemate. And once i told him about one of my fav show and his respond was “my housemate likes that too”
But he said he likes me and wanna continue seeing each other and doesnt wanna go backward.
I know im probably crazy becuse im jealous for nothing but its killing me. She is really pretty and hes really charming. Im thinking off moving on and just let him go. Its killing me. After all im not as pretty as her and he doesnt even know me that much or care about me.
I dont know what to do about it. Help me

Hi--

First thing I would say is that I don't think your jealousy is irrational- if the guy you're seeing keeps going on about his housemate and you think he has feelings for her I would say to confront him. Or maybe, start talking about a guy in the same way he talks about this housemate to see if he gets affected the same way you do- your guy talking about another girl while he's on holiday with you is just a load of bs- he should be focused on you. But personally I think honesty is the best thing in these kinds of situations- maybe he just really cares about her as a friend and doesn't realise that bringing her up affects you. Talking through it in a sensitive way would be good. But from personal experience, if you feel like he's neglecting you and not treating you right and if he still goes on about this girl, then just drop him girl. Don't put yourself down and compare yourself to others because you sound like a beautiful soul- know what you deserve. Maybe you'll be happier with someone else. Ask yourself- is this guy worth it? Does he make you laugh, does he make you feel good and special? Do you see a future with him? If the answer is yes, then don't worry about this housemate, confront him about it, make him forget her by reminding him how amazing you are! Let him get to know you, he'll forget all about this housemate trust me. If the answer to those questions is no, forget how much you like him and remind yourself of the way he makes you feel. Don't put in more than you are getting.

Hope this helped
Message if you need any more advice