Wedding to Be , Second Thoughts Or In My Head ...

Jay has become my best friend. He is the one I have the most fun with but we are two very different people in another sense. Jay and I are on the same wavelength when we are talking about going out, having fun, etc... From a life POV we are completely different. I am a very capable person that constantly takes my future into consideration. I have always done well in school and have a good job. He on the other hand is a lot older than I am but has a very unstable career, always getting discharged or not getting his work contracts renewed. He is not always as capable as he should be. (I hope this doesn't sound bad, but if I want a truthful opinion I need to be honest) I think as a man in his thirties he should have money saved, a good stable job, and not need my help for every little thing. It scares me that we are now getting married and again I am being thrown into a situation where he does not have a job. (He recently found out that his contract is not getting renewed) The only reason he has found his last four jobs are because I have helped him and when he does have a job, he doesn't make that much money. In his past he had numerous one night stands and other relationships but he was never even close to getting married to another girl. I know he loves me and would never break up the engagement, but I feel as if I have been thinking about "what should be" more and more. I think my family's comments may have something to do with this. They always say that I hope he realizes what he is getting, b/c you are the best catch out there but he doesn't have much to show for his life. (Not meaning only financial stability, but he lives with his parents, and not as competent as he should be, needs to be more proactive in his life, have a foundation for the family he wants, be able to support them, etc...) He was my first (sex), I truly gave him everything I possibly could and in return I got an STD that may lead to cancer. I have gone through a very hard time with things he has done to me or how he has made me feel, but in my heart I know how much he loves me and that none of it was intentional. He had gotten tested twice before for STD's on my request. He is not a good communicator, we think on two completely different levels. If my parents knew that he gave me soemthing that can be life threatening they would be so upset that there is no saying what they would do. They don't even know that he is out of a job again. I have to constantly lie to them so they don't know what his past really was or what he may be able to do or not do for their daughter's future. (They know I have always wanted to stay home with the kids a few years so I can raise them) He has cheated in a past relationship (before me) and has even slept with a married woman. I know this stuff was all in the past and I should focus on the future, but I can't help but think "how could he?" I would never do that IN MY LIFE!!! I know as a fact that he would not cheat on me, but I cannot say the same if alcohol is involved. When he goes out with the guys (very rarely) they drink and he ALWAYS drinks too much. Not to the point where he is puking, but where his words are slurred and his eyes are bloodshot. I worry that this can lead to something bad, like making out with a stranger or something. He tells me that I worry too much and that I'm anul. I really do feel like he is getting the better end of this deal, but he is a good person with a good heart. He does want the same things out of life, a family, a house, and kids. He is very good with kids and does take pride in me. I am not sure if I am just experienceing anxiety or if I just think too much b/c I never thought I would be marrying someone like him. Any thoughts are appreciated.