How can i trust my boyfriend more? I Love him but its hard to trust when i have had 3 guyes cheet on me?

I have been daiting a guy for 1yr and 1/2 and i love him very much when he goes out iwht his friends i think that he is cheeting on me bec. my last boy friend cheeted on me 3 times how can i learn to trust him ? How can i help from not arguing so much Please help