Tense

Are you sure it's tense that's the issue - not timeshift? You can have scenes from different times (headed up by the year as you've done here) without necessarily changing the tense.

If you are going to change the tense, do you mean that you're going to write the present day scenes in present or present continuous (eg 'I take her hand' or 'I am walking down the street') and the earlier scenes in past tense (eg 'I took her hand', 'I walked down the street'). I think that could be interesting. I imagine that writing in present tense might give a rather breathless feel to the scenes, certainly a sense of not knowing what's going to happen next. Have you ever seen the film Memento? It's years since I saw it and my memory might be wrong, but my memory is that the main PoV character gives an overvoiced narration throughout the film. This narration is in present tense - as in he's narrating what's happening in real time as we see it on the screen. This does give a particular quality to each moment - it's like every moment is new and out of context. It's important in that film, because he has a brain injury that affects his memory, and so basically he's living constantly in the present tense. I know it's a film, not a book, but the narration is a script essentially, and it might be worth a look (great film too!) Bright Lights, Big City was also in present tense as I recall (and similarly breathless) but that is rather oddly written in second person (eg You are walking down the street. You've been here before). After a while you stop noticing the second person and essentially treat it like standard third person (or at least I did). Again, the present tense is relevant because of his drug habit, as the present tense gives us this super-lucid stream of consciousness effect. You might want to think whether present tense suits the story - is there a good reason for having it in present tense? Typically, I think, we all go about our lives with a sense of ourselves as continuous beings - I mean we're aware of our immediate past, our distant past, our immediate plans, our hopes for the future. There are times when we become more intensely aware of the present moment - like if we find ourselves with stage fright in front of a crowd; if it's a (you hope!) never-to-be-repeated moment, like your marriage vows; if it's the few seconds of flying through the air after a car knocks you off your bike. Do you see what I mean? The intensity of those moments can be conveyed through present tense, but I think it might be uncomfortably intense for long passages.

I think you have a bit of pluperfect in your example, the 'had' tense 'I'd rolled my eyes'. I suspect pluperfect has a very distancing effect on the reader, giving the impression that this thing is over and done, and is kind of irrelevant and please can we move onto something else. You need it sometimes, of course, to say 'I had done X and then Y happened'. But I would think you need to use it sparingly.

Be prepared for a long read, it's about fifteen hundred pages long.