jump off the deep end

jump off the deep end (over someone or something)

Fig. to get deeply involved with someone or something. (Often refers to romantic involvement.) Jim is about to jump off the deep end over Jane. Jane is great, but there is no need for Jim to jump off the deep end.
See also: deep, end, jump, off
References in periodicals archive ?
COVENTRY'S Gabby Logan refused to jump off the deep end for new TV entertainment show Splash
But rather than taking the middle road, M&S home furnishing has just taken a jump off the deep end and is entering a new era under the visionary direction of retail guru Vittorio Radice who was responsible for the turnaround of Selfridges.