Help with relationship issue?

Main topic of this issue mainly applies to lying. When I think about something, I find that it’s best to not tell, since I find that if I tell it’ll hurt (of course until one has found out then it hurts more…) the person you tell it too. Mainly applying to the one that’s in the relationship with you. I know that you should tell your S.O what you did, so you can be the honorable, trustworthy person you are…Well…I don’t know what the hell my issue is! I have lied to my S.O too many times, and it’s making her feel like one I don’t care, two I am a liar (I don’t want to be labeled that personally since I try my best not to be, even with the small things..) and three that I am untrustworthy (I think I am… but not in a narcissistic way.) I keep screwing up with this very small, but deadly thing. I don’t like to lie that much… and I wish I didn’t have to, but with the mentality I have I end up lying and I really. REALLY Don’t want to…Yet I tend to do it again..And again, and quiet frankly it’s very. Bothersome, to me emotionally and physically and to my relationship. What can I do! I know from experience with talking with a few other guys they seem to have the same mentality as me. (I lie since I want to protect you not hurt you.) Please, does this happen with the other guys that are out there? What to do… I really need advice.