Boyfriend of 5 years, need advice..

Hey everyone! So when I first met my boyf like honeymoon stage things were exciting and he'd always made sure I was okay when I wasn't all that stuff I felt so loved. But overtime we all goes through some bad patches then when and accept little things of each other but apart from that my problem with him is trust. We live together two years now. He knows I'm not okay with him spending all these nights out (all night long) leaving me on my own, whether I'm back from work or not, the thing is he knows I'm okay with him having a few enjoying himself as long as he lets me know and not take it too far also to keep in touch and let me know when he'll be home. The nights out are not as often nowadays, I keep on having faith in him after so much stress and lonely nights I've put up with. Talked it through. Couple weeks ago he's been out with his mates, I was cool when he's messaged to tell me as I got home from work. But messaging his mate and him telling me that my boyf is with him in his house playing Fifa was a lie. My boyf was back later than expected. His mate messaged me to tell me he will be back home in half an hour, taxi is phoned, and that it's not came for him apparently so he phoned another one. About an hour or two later still no sign. So I messaged to his mate to say he's not home, his mate messaged me to say he's left. I like my boyfs mate until I found out that he was lying. When my boyf got back eventually he was so fired up with the drink, insisting to go back out.. I told him how I felt how upset I was waiting on him and that is rather he stay. So he did, changed his mind to stay with me I asked everything.. And he told me he was out with his mate and not at his house playing Fifa... Ridic! Anyway, most recent night with drinks was when he was off work, and I had work during the day, only 5 hours, but anyway we made plans in advance to just stay in and he will make the dinner for me getting back home. So I got home but, he was obviously out. I was cool, checked my messages to find that he was out with his dad for a few drinks and that he'll be back to make the dinner at half 8. The time came and passed, over some more time he messaged from his dad's phone to tell me he'd be back in half an hour.. Half hour later, still no sign, and I get another message asking what I'm dong and that he'd be back in 10mins, still no sign... So it's 11 o'clock (not as late as what he used to be, it just seems so piss taking for him to do this to me! So my mate came over with some drinks, and me the boyf and my mate were having a drink some arguments involved due to me being annoyed with his lies about coming home at the times he says and bringing up the past of late nights.. I just had enough and he was so drunk and didn't care how upset I was, so I threw a drink in his face and he pushed me over on the sofa, not heavily though I wasn't hurt.. So he's got angry that I did that, I told him why and that I was sorry I cried loads that night. We carried drinking and tried to make up then my mate went home, we went to sleep. We've fallen out over things (no cheating involved) but made up. Im staying over my mums for two nights. Just now he's logged into his FB on my iPad and forgot to sign out and because we've fallen out not getting on that great, tonight he was out with his mates got in early messaged me, we talked and I was obviously still kind of annoyed giving him the cold shoulder and no kisses on end of messages, and he said he was drunk... I was able to access his FB (he doesn't know) to then discover and find he messaged some girls two other of his mates asking everyone who is going out, not many replied. But one particular he seems keen on to chat with same time as me, which made me feel so insecure, it was general chat but it's late and he's been making effort sending silly emojis and asking what she does and that he's going to annoy her and just making convo with her, at the same time small talk convo with me but not saying as much, really upsets me that he's doing this, the girl was not flirting she was just replying to everything and making convo.. We only just met this girl and a couple of other people two weeks ago on a night out all together, random but added on FB, he's never messaged any of them not that I know of and I'm now suddenly finding him asking all these questions to this other girl looks so bad to me, so I messaged to same girl to say how she was, it was a great night we should do it again sometime and that me and the boyf isn't getting on that well at the moment and I don't feel I had anyone to talk to. She messaged me back to say sorry and that should come for lunch or drinks next week I said yeah sounds great. Then she messaged my boyf which I saw the convo, saying what's up with you and your girlfriend? And then he told her that we've not been getting on for 6months!! Yes we've fell out a few times but was minor and we made up and was the happiest past recent while apart from when he ditched me i was kinda getting over it and he said sorry. But isn't this wrong, I'm so confused of what to do with myself, I love him and wish I had him to myself and all of it to go away.. It got late the girl didn't reply I think she went to sleep. My boyfriend messaged me a bit then eventually he's off to sleep and I've sat up all night at my mums awake and worried.. I'm going back to stay in the flat with him tomorrow. It's gona be awkward.. What does everyone think I should do?