If you are lonely in London and don't speak French, if you move to Paris, it will knock the loneliness you feel in London into a cocked hat. Hate the weather in London? It rains more in Paris.
I don't mean to piss on your parade, but do think very carefully about it. The bureaucracy in Paris can grind even the most cheerful person down - if you don't speak French, and your partner does, this will put a huge burden on him, as he will have to sort out parking permits, electricity, utilities, make all the appointments for the doctors and dentist (because although there are a fair amount of English speaking doctors and dentists, the receptionists rarely speak English). And there is nothing more rage inducing than getting phone calls at work when you're in the middle of a meeting - there's a man here, I think he wants to read the meter, can you speak to him? Can you book an appointment at the dentist for me, and explain that my filling is loose, and I don't want it replaced with amalgam, can they do a white filling in its place? And having to book leave to go and deal with the parking permit people because the person at home doesn't speak enough/any French. (My DH worked from home - while he was used to it in London, he found it profoundly depressing in Paris - it was the lack of easy interaction with the outside world that did it for him, and a lack of friends, although he did make some.)
And in Paris, if you are not very confident at the language, some of the people in shops will delight in giving you entirely the wrong thing (actually, they do this with most foreigners, but it can destroy your confidence if you aren't very good at the language). It can be amusing, being given a millefeuille instead of six eclairs, the first time, but by the third time it happens - or if you just go into the bakery and ask for a baguette and they look baffled, shrug and serve the person behind you, it can grind you down.
Yes, it's a pretty city. But it's staid, middle class, middle aged and dull (that's my French neighbour's assessment, not mine - her son moved to London and she said what a lively city it was in comparison). Lovely for a holiday (but mind you don't tread in any of the dog shit that lines the pavements; very few people pick up their dog poo and there are millions of small dogs), fabulous restaurants, but so, so conventional. And never mind being the city of love - I knew five couples who split up in the four years that we were there. French divorce law, if that is where you are deemed to be resident, is not kind to the one who earns less...