Japanese and UK citizen want to get married but one on incom

Dear Sir/Madam

I have a question for you hope I get your advices:
I’m a Japanese national, male 40year old, I want to get married with my girlfriend who is a UK citizen and lives in UK. She is on income support program at the moment, can we get married? However I have some saving that I can take care of myself financially at the moment until I find a job in UK so I don’t need or seek for any public funds for myself in UK. But I can’t cover my girl friend’s life expenses either. Especially she has a kid. Can we get married and his financial situation stays the same as now, and I take care of myself until I find a job in UK? I know I can’t work in UK until I get my work permission in UK, and to get working permission I need to have a spouse visa.
Please give me some advices.

Thank you in advance

Sumiko