My reasoning is this. With a son of 19 years of age your wife isn't just
starting out on her career. In some areas of law the average high street
solicitors pay is £27k-£40k. If she works
full time pro rata she will be earning £37.5k or less. Potential income is
just one factor taken into account, another factor is the lifestyle and
work/child care balance during the relationship.
In this
particular case there is one 17 year old and a 19 year old in higher
education and it isn't unreasonable for them to be provided with a
base with your wife whilst studying for a first degree. That
should be balanced against your need for housing.
SM has to be
seen in context of the overall facts and the particular details. The first
consideration is whether a
clean break can be achieved and just because your wife
is looking for a 50% share in your business doesn't mean she will get it.
If she is the higher earner your wife will be able to raise a
larger mortgage than you so that justifies a larger share of capital in
your favour than would be the case when the parent with care is the lower
earner. Because of that you are likely to have a lower mortgage relatively
speaking which decreases your need of SM and she will have a higher
mortgage decreasing her ability to pay SM.
As I said above
based on the limited information given I doubt there will be
enough discrepancy to justify much in the way of SM but as YA said you need
independent
legal advice about your individual
circumstances.