My friend is in a toxic relationship and it's impacting our friendship

My long time friend has been in a relationship with this man for a year. He is extremely controlling, gets upset with her if she goes out with me, or on her own. Gets upset if she doesn’t see him to see her parents. We met at this event few months ago, where she didn’t know a single soul but me, and he got upset because she left him for 10 mins to come and say hello to me, and because she was looking around her. He decided she was trying to flirt with another guy to his face. They argue several times a week, sometimes he calls her names, most of the time after they argue he turns his phone off and becomes unavailable. So yeah, seriously abusive.

Before him she had a 20 year long relationship with a guy that kicked her out of the house for four years, before she found out he had another relationship. Two years ago she broke up with him.Around the same time, we reconnected. We were best friends in high school (age 13 - 18) and kept in touch over the years but only two years ago got closer again. We are now pushing 42, so we known each other for almost 30 years.Anyways, as soon as she started recovering from the breakup, she met this one and immediately developed a crush. She dated another one before this, briefly, and she also got an immediate crush. Basically as soon as a guy that she finds slightly attractive gives her attention, she falls for him.

I have been trying to tell my friend that she needs therapy and that she is once again a victim of abuse and that she needs to leave this guy. She agrees and is rationally aware, but is deep into it and she says stuff like: “I know but I’m too good and I see him as someone wounded”, “I believe with love everything can be fixed and he can heal” “Compromise is necessary in a relationship” “I love my partners like a mother loves a child” “he has to understand that he is wrong and I don’t want to give him the satisfaction of leaving him” and “I know this can’t work but I want it to end without drama”. The other day she says that after an argument, when they reconcile, she sometimes thinks “he might be the right person”. Sometimes she mentioned considering renting a flat with him and wanting to start a family (I strongly advised her against this more than anything else).

The situation she is in, is having an impact on our friendship.

We only saw each other once since she started dating him last year, in spite of living only 15 mins drive away from each other. She doesn't say, but I know it's because he doesn't want and she tries to minimize drama.

Every single time I hear from her, she keeps telling me that they argue, she cries over voice notes, and we go over the same conversation - me telling her she should break up, and her telling me all her yes buts. It’s extremely heavy to me.

For the last two years it’s been looking very much like a therapist - patient relationship.

She obviously doesn’t have any bandwidth not only to support or listen to my problems if I needed to vent or needed any support, but she is also not available to go out and have a little fun (because then the guy gets upset etc etc). She is highly educated, fluent in several foreign languages, and an employee for an important government office. She isn't dumb or uneducated and she is aware.

I’m genuinely worried about her and I don’t want to isolate her. On another note, I realize if I met her today I wouldn’t have befriended her. We used to share a love for music, linguistics, grammar and silly jokes. She now only seems interested in men, specifically the current and the ex.

I know I can't help her because yes she is unhappy, but she seems to prefer this situation to being single. I offered suggestions for therapists, offered to go with her, offered to book it for her. She says thank you and goes on as usual.

I am considering telling her to reach out only once she broke up with the guy, but I also don’t want to be the shitty selfish friend that abandons her at her lowest. We all know that past 40, making new friends isn’t easy and being socially isolated is tough.

What do you think? What would you do?