I've seen some real good advices on here so I thought I could ask,this is going to be a long post so please bear with me.
A really close friend of mine is battling and I don't know how to help him...
He has been in an intense relationship for quite a while now with a girl who has 1 kid with another man(prior to them starting to date),he loves the girl like really love her and also love the daughter as his own. When they started dating all was good until he stumbled on some messages(inappropriate) between his lady and the daughter's biological father,obviously things went south,she apologized he forgave her but didn't forget the trust was lost they started fighting everyday 3 months down the line she broke up he let her go but 3 months after again she was back they started dating again for 4 months and then broke up again,they both started seeing other people then 10 months later they both left the people they were with and got back together again for 4 months again then broke up again,5 months down the line they were back again in each other's life,the girl has been going through a lot and the guy has been there for her he has been there for her since day 1 they started dating,always trying to get her whatever she needed so now the guy still want her back but the girl doesn't want to well that depends on her moods,when in a good mood she wanna be back when in a bad mood she doesn't even wanna hear about it, sometimes she says she still has feelings for him sometimes it's she just loves him as a human being but not more sometimes she doesn't love him at all,she has asked the guy to decide where to go from now on,he said they should get back together and work things out,she says she agreed to get back with him because she felt obliged she owes him a lot and feel like she has a chain on her neck so she has to say yes to everything he says.
Now the guy is battling with whether to stay and fight hoping that things will get better with time and that the spark/love will come back or whether to let her go AGAIN?
They both have their wrongs no one is perfect and no one(including myself) around them wanna hear about them together again it has been too much they hurting each other but he's a friend I can't give up on him.
Any advice especially from the ladies would be really appreciated.

I was waiting for you to slip up and say "I" or "me"instead if "he" or "him". I'll leave this one to the ladies because TL:DR properly.

From my personal experience, I'd tell your friend to run for the hills.

Been with someone like that. Here's it panned out after a lot of years, I mean double digits. She likes/needs someone to be there for her and help her out but never really loved me although she put on a good show (in your case, probably still loves baby daddy). We also fought all the time because of that reason,bit was her way of creating distance because of how she truly felt although I never knew this the whole time until that day came when she finally admitted that she doesn't love my but loves what I do for her and having me there to do it. She was also a perfect 10 looks wise which blinds the sensible brain eventhough she could hold out on me for 6 months at a time yet I stuck with her and hence ended up here to meet my needs, assuming your friends girl is a hotty too.

Far easier for him to leave now with some heartbreak than later with divorce, kids and maintenance and stuff with her in his life forever while watching her move on with someone else, maybe even that baby daddy. And to top it off, she gonna take half his hard earned wealth. That's my opinion. Just not worth the drama.

Run forest run

Sorry to tell you this but your mate is a beta cuck, who is been used for financial / security while the woman gets her alpha fucks elsewhere in the hope she gets to trade up.. tell the guy run for the hills and find someone who wants him, also tell him to man the fuck up , after 30 there are a lot more fish in the sea for men than for woman she will end up screwed not him.. as for the emotional attachment to another mans child well that ain't really something he gets to control , I am sure that type of woman will use it as physiological leverage over him so he should cut that shot out as well..

Tell your friend to run for the hills.

I've been in a relationship with someone like that. The circumstances were very different, there wasn't a child nor was there a single other man whom she clearly loved (I think she loved many other men).

At the time that I dated her, I had never known a better relationship (and it didn't help that she was hot as hell) and I thought that was normal. It was only later, when I met someone who cared about my own needs as much as hers and who was loyal to me and only me almost to a fault, and made me a priority while I did the same for her, that I realised how unhealthy and shitty that past relationship was.

What sounds familiar is the lack of selflessness. The lady seemingly dates him only to serve her own needs; there is no synergy and she may be parasitic. She is still in love with her baby-daddy, and likely treats him different to your friend too. She probably actually cares about her own needs and cares for him only as far as he can fulfill her needs.

Your friend also, seemingly, needs to be needed. He sounds like he's got "captain-save-a-ho" syndrome and must address that as a matter of urgency. I don't know what he gets out of being with this woman but I bet that it's got nothing to do with what she does for him nor how she treats him.

Let's also consider her daughter; the only victim in this scenario. She needs stability. She doesn't need to grow up seeing this kind of on-and-off relationship as normal, it isn't and he isn't helping her in any way there.

The best thing he can do for himself is to get out. Delete her number. Forget about her. Delete her pictures. Unfollow. Unfriend. Then work to find himself a woman who'll reciprocate his own selflessness

He needs to research words like:
Co-dependent
Narcissist
Trauma bonding
Hoovering

If he is unwilling to face either what he is or what she is, nobody can help him.
So also stop wasting your own time to tell him what to do/give unsolicited advice.
If a person has not experienced enough pain to learn the lesson, the lesson will continue.
Give him the list of words, and simply say that you are not being a good friend by supporting him in his addictive habit. He can do his research, and knows where to find you, once he is ready to face the truth and needs support. However, you also need to take a step back, cause your continious support of a person who is clearly destroying his own life, whether it be with drugs, alcholol or toxic people, is not really helping him.
As a survivor, with experience, I know what I am talking about.
Kisses, Mynx

To put it succinctly, she is a nutjob, and your friend must cut the strings, or stop whining

@Tegwane...when one is psycologically stuck in a Stockholm syndrome type realtionship, it is very challenging to exit. This is why so many abused people stay so long in toxic/abusive relationships.
It does help a lot to have the words to research to firstly understand wtf happened to you (how your reality has been distorted and manufactured to keep you trapped), then to understand wtf you are actually dealing with (it is not human in the normal sense, and thus cannot be approached in any way a human would be approached), thirdly to understand you are not alone(there are people who actually really understand, have lived the experience, and therefore truly understand) and lastly, there is a formula for helping yourself and a formula for freeing yourself.

One cannot in fact, tell a person who is living a nightmare, to simply snap out of it. However, I maintain...if they are not willing to face the truth, nobody can help them.
Kisses, Mynx

This must be a first, everyone agreeing. Run, then when you get away, run some more then when you get where you think you are safe change your shoes and run some more. Best explanation is alpha cock /beta wallet. Brilliant.