So I have this very good friend, we have known each other for like 18 years now. There was always a spark of rivalry between us and I think that is part of what keeps this going.

Anyway, he is in a LTR for quite some years now. They got together when the girl was 16 and he was 18. She was like REALLY into him but after that it went straight downhill. They are together for 6 years now with one almost a year break that was initiated by her since she felt like she was missing out on things (read: didn't get to ride the carousel). She rode it a little, he got some things going on as well in that time, but told me that it felt so empty compared to this girl.

The situation now is terrible. They sleep together once in a month and it's actually her who complaints about it. She tries to have sex with him quite often but he always says how tired he is from soccer with friends and often rather goes with buddies to pub just to avoid her trying to fuck him. The obvious conclusion of this is that she sleeps with other dudes, she sometimes even hints something like that to him and he is like "I wouldn't be surprised.". When they actually manage to have sex, it is (according to her) always the same boring routine with the exact same script, position and etc. When she complaints about that, he says that this is the way he likes it.

His version is that he is under so much pressure that the sex doesn't give him too much pleasure. But the problem is that she is his oneitis, and a rather big one at that. She tries to break up with him time to time and he always "convinces" her to stay together, that it will get better, etc. Finest example of negotiated desire and how it doesn't work.

Last time, he got a mortgage for an apartment and they started to live together (which he said to her will improve stuff - it didn't of course).

I would like to get him out of this terrible relationship but I don't seem to be able to do that. He responds very rejectively to any redpill truth I try to give him. I know about the first rule of TRP but this guy needs it so much and I have no idea how to help him.

Anyone in similar scenario? Any ideas?

edit: typos