Lampard's relationship status has just changed to "It's complicated"

It seems trivial, in this week in which we commemorate the outbreak of World War I, that football rivalries should even be an issue. And they're not.

That is partly because the season hasn't properly begun (any semblance of footballing activity is the result of that annual charade of pointless but neat money-spinning pre-season "friendlies") and partly because, in the scheme of things, the slaughter of a generation between 1914 and 1918, pushes everything else into a very distant background.

But allow us some levity in a week heavied by history. Because if there is one thing football fans struggle to accept more than anything else, it's seeing a beloved, loyal, serial badge-kissing club servant playing for a rival. Any rival - and not just the cross-this-postcode-and-we-condemn-you rival.

If you don't care much for football this might seem particularly trivial and, probably, part of the reason you don't follow football to begin with. Because, yes, it really isn't that important, is it?

But let me frame it differently: you've just undergone an acrimonious split from your former significant other. The pain is still quite raw. The next thing, you see her Facebook status has gone from 'In a relationship' to 'Single' to 'Engaged' with the same sequential speed as traffic lights at a busy road junction. Yes, it's that painful.

I'll cut to the chase, then: no sooner had we Chelsea fans accepted that our 12-year marriage to Frank Lampard was over than he was pitching up in the Big Apple doing that footballery thing of talking about sharing in the vision and ambition of his new club, New York City FC. "OK," we said, "life goes on and so must Frank. Good luck to the fella."

But, then, just as we were sizing up his new club and concluding "nah, not much...", it was announced that Manchester City, New York City FC's parent club, would be taking the 36-year-old midfielder on loan "to maintain fitness" until the MLS season begins next March. This morning Lampard arrived at Carrington for his first training session with the Premier League club. In Joe Jackson's words, "If my eyes don't deceive me, there's something going wrong around here."

The loan means Chelsea will get to play their former vice-captain at least twice before he starts his new American venture properly. David Villa, also signed to New York City FC, will play his preparatory loan spell in Melbourne which, I'm sure, would have suited the Chelsea faithful as Lampard's temporary hangout.

Picture courtesy of New York City FC

Frank is, however, an intelligent player. It's unlikely he'll be tweeting pictures of his American-funded engagement stone and I'm sure we won't be enduring gushing congratulatory messages from his nearest and dearest. He knows his future value in some capacity at Chelsea - Roman Abramovich has apparently said so much - and being the supremely diligent professional that he is, he'll take the wages and get on with his job, no matter who that job is for. People, we have to get over this notion of club loyalty in the modern era - you play wherever someone is prepared to pay enough to keep you in new Bentleys and Ferraris.

So, taking spurned pride out of the equation, rank-and-file Chelsea supporters shouldn't mind, in principle: Lampard is one of the greatest players ever to wear the Chelsea shirt and will always be regarded so. Players leaving and players arriving, however, is part of life - someone has to be disappointed.

There is, though, the small matter of that quote last year when Lampard said that, after 12 years at Chelsea he couldn't imagine playing for another Premier League: "I couldn't do it".  Well, clearly he can. That shouldn't be a reason for resentment, as a chap's got to earn a living. And it won't be the first time Chelsea supporters have seen a hero pitch up in adjacent quarters: 1950s hero Roy Bentley moved to local rivals Fulham, Jimmy Greaves went further a decade later to Spurs via Milan, the King of Stamford Bridge, Peter Osgood, left for Southampton (in the days when they were a buying club...), and both Ray Wilkins and Juan Mata have moved to Manchester United which, at one point in time would have been far more difficult to countenance than a move to Manchester City.

What backlash there has been so far has been tame. Pat Nevin - who himself left Chelsea for Everton, and yet is still held in the highest esteem at Stamford Bridge - says Lampard's loan appearances for City won't be a problem: "It won't damage the way Chelsea fans feel about him long term," he told the BBC. Supporters' groups agree, noting that despite the inevitable trolling from a minority doubting past pledges of loyalty, the majority won't feel slighted. Most grown-up footballer supporters recognise that under-contract players tend to go where their parent club tells them to.

In fact, the strongest words of dissent have come from Arsenal manager Arsène Wenger. Doing nothing at all for his 'voyeuristic' reputation in José Mourinho's eyes, Wenger has questioned the legitimacy of Manchester City paying Frank Lampard's substantial wages during his loan spell (there have been murmurings that Lampard coming to Manchester - as opposed to the rumoured Melbourne where David Villa has gone on loan - was a ruse to bypass Financial Fair Play commitments).

Lampard will become one of Manchester City's minimum five homegrown players needed in their Champions League squad to comply with the UEFA rules on financial integrity, something they have bitter experience of failing at, following their fine and restrictions on wages last season under the FFP rules, and having to make do with a 21-player squad for this season's Champions League.

All this, however, is academic. Because the crux of the matter doesn't lie at UEFA headquarters in Switzerland, nor does it lie in the bills section of Lampard's wallet. The location of potential pain lies in Lampard's feet. We've been able to see Chelsea players go out on loan and not bother us - Romelu Lukaku's prolific loan spells as a striker at West Brom and Everton probably did Chelsea a few favours; but when no playing restrictions apply, and a sold player still has the potency to do some damage, then that is when things turn sour.

Lampard is, though, too smart to start kissing new badges, and we certainly won't expect any goal celebrations, should he be able to beat either Courtois or Čech in the games between Chelsea and Manchester City ahead. But that won't make it any easier.