<human>: Hello everyone,  I [25F] have been dating my boyfriend [29M] for 4 years now, we live together, he is wonderful, we have so much fun and I generally enjoy my time with him. The issue is that for our entire relationship I feel this urge to break up with him, it is a presence that pops up every 6 months or so in the back of my mind. There is nothing wrong with our relationship that would indicate we are not compatible, and when we are together I feel so content, happy and excited to be with him.

I felt this way in the beginning, and thought it was just new relationship jitters but this feeling that we have no future and we should break up has never gone away. When we set out to make a decision together, inevitably I'm thinking to some degree, 'how easy is this to back out of if we break up?' I feel terrible and have told him about this many times in the past and he has been supportive and encouraging about our relationship. I haven't brought it up in the last couple of years because I don't want to hurt his feelings. I've talked to girlfriends about this but because its ongoing and I love my boyfriend so much and have stayed with him they all just 'know' that we will be fine and be together.

He has been ready to take the next step (marriage) for some time now and I have bogged us down because of this 'feeling'. I even tried a break for a couple of weeks and all I got out of it was that I love him and don't want to not be with him but I still feel like we should break up. I feel like I should just go with my gut and leave because I don't want to be like this forever, but the thought of leaving him is so scary and I don't want to hurt us both for no reason. Advice?

Can you summarize the given text in a few sentences?
<bot>: Perfect relationship except I want to leave? maybe? for no real good reason except mysterious feeling telling me I want to.