Fianc'e Problems- Lack of Intimacy and Online Fling

I've known my fianc'e for almost six years, been dating five years and engaged the past six months. We are both in our mid/late 20's. We get along extremely well, have the same interests and life aspirations. We click on so many levels, enjoy each others company and are all in all a great fit for each other. All would seem like it was going fine looking in. However, there are small cracks in our relationship that are starting to worry me. I know having regular sex is only a very small part of a strong relationship, but we have not even come close to anything intimate in the last six months. When we get into bed at the end of the day to go to sleep, it is a quick peck on the cheek to say goodnight and then we both roll over and go to sleep. I try to cuddle and kiss a little bit longer. I try to initiate some sort of physical touch but she is never interested, always saying she is tired, not that into it, or just snaps at me saying she isn't in the mood. I've tried the talking through our problems approach, which has worked extremely well in the past for other issues. I've asked her is she still attracted to me, does she find me physically attractive, why she doesn't want to do anything intimate, etc. She just says she just isn't that into it anymore, is tired all the time (from work and exercise and life in general). I've tried arranging date nights, cooking her chef inspired dinners, picnics in the park, weekends away but nothing seems to work. I'm feeling pretty helpless and don't know where to turn. I feel awful for doing this, but recently I've signed up for an online "fling" website, which is like online dating but the reason for meeting up is obviously different. I even went as far as topping up the account with $50 of real money to but "credits" so I could message people. I've got to the point where people have arragned a meeting time and place and wanted to exchange phone numbers. When ever it gets to that point a huge amount of guilt and dissapointment comes over me and I always pull out and not talk to that person for fear of meeting them, sending my world crumbling if anyone ever found out about it. The reason I joined is because I wanted some sort of excitement and the feeling of a woman 'wanting me physically' which I'm not getting at all with my fianc'e. I feel terrible for doing this. I'm really quite stuck. I'm frustrated with the situation but when I try to fix it with my fianc'e it isn't happening. I understand she just isn't into being physical and sex was never a big part of our relationship at the beginning whilst we were dating (perhaps having intimacy once every fortnight or so). Where do I turn? What do I do? I love this woman deeply but I feel stuck.

Those aren't small cracks. "I know having regular sex is only a very small part of a strong relationship," No, it's not, it's huge! Don't believe the excuses-making hype. Without that (and the rest of the romantic expressions and demonstrations) you two are just friends. "or just snaps at me saying she isn't in the mood. " What is she resentful about? Basically, you've done everything to re-woo her and she's not responding to it. Has she no needs any more? Or are her needs getting met elsewhere? "I'm feeling pretty helpless and don't know where to turn. recently I've signed up for an online "fling" website," Well, where you turn is NOT THERE for starters!! No, you are NOT 'stuck', don't be ridiculous. You should be telling her that unless she behaves remotely like a woman still in love (and enough to last a lifetime) - which includes telling you what's up and why so that you can both FIX it! - then you see no point in cementing that status quo for life, meaning the engagement is off and will not be on again unless she starts doing HER share of boat-rowing with you (because you're fed up of going round and round in circles), and that if she fails to, the entire relationship will be off. That's the honourable thing to do that *won't* in the process involve you damaging your own self-esteem by becoming a rotten, low-down dirty cheater. Your choice. And then, duly free and available, you can find a new and improved relationship worth having, the LEGITIMATE way. It might be her if she realises what she had before it was gone. Or it might be another (better suited) woman. You know I'm right which is why you can't follow through with cheating to begin with. GOOD. You don't have to start self-harming like you're actually trapped in this relationship. You're no such thing. Resentment blocks libido. Resentment produces snapping at what is actually a nice and flattering request. WHAT IS SHE RESENTFUL ABOUT? And we're talking long-term build-up. Or is she not resentful but GUILTY? Or BOTH? Is she however much involved with someone else? Do you see any signs of another man sniffing around behind-scenes?