My man.....sorry so long had to explain...?

I am completely in love with my boyfriend. We were together on and off starting last september for about 6 months...and then took a break over the summer for about 7 months. We are now back together and have been for almost 2 months...it's been going great. We've talked about getting married after college and he seems totally serious about it. He has even gone as far as subsituting his last name for mine when we're talking to people. We didn't work out last time because of his relationship with a couple other girls...so this time i'm a little weary......I'm having a hard time looking beyond the past and trusting him....any suggestions?