I think it’s over

My boyfriend and I have been together for a year and a half tomorrow and i don’t think things will last much longer... I had to gain his full trust because of the women he’s been with but I’ve always been faithful and honest... recently I’ve been concerned about some women that are following him and talking to him and stuff, when I ask, the messages get deleted... sometimes I don’t have to ask and the messages are gone. Like he’s hiding something. He’ll even deliberately put his phone in another room sometimes. We argue a lot and it just seems like we’re going way downhill.. I’m heartbroken to even think that he’s possibly flirting with another woman but I can’t help but think he wants someone better. I don’t know what to do and all of the people I have that I can talk to only say “dump him” not give any actual advice that could help... I just don’t know what to do anymore

*edit* I had my friend over last night and she brought her son so him and her son could hang out and play games and such and me and her could hang out, well bedtime rolls around and (he’s a very nice looking guy with a nice body) and he comes out without a shirt on, like knowing that another woman is in OUR house. I asked him about it and he apologized but if he meant it why would he do it in the first place... this is the same woman whose messages he deleted (along with two others)